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Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

Summary

Background

Effects of frequent nocturnal symptoms of gastro-oesophageal reflux disease (GERD-FNS) on health-related quality of life (HRQOL) and work productivity are not well documented.

Aim

To assess symptom severity, production loss, and HRQOL among employed adults with and without GERD-FNS.

Methods

Using several validated outcome measures in a web survey design, GERD was pre-specified as GERD Symptom and Medication Questionnaire score >9, and ≥1 episode of heartburn or acid regurgitation during the preceding week. GERD-FNS patients were those reporting ≥2 symptom-nights during the previous week; their outcomes were compared with those of patients having minimal or no nocturnal symptoms (GERD-NNS) and vs. non-GERD controls.

Results

Data were collected from 1002 GERD patients (476 GERD-FNS, 526 GERD-NNS) and 513 controls. Severe symptoms were more common, sleep abnormalities were more frequent (P < 0.0001) and SF-36 scores lower (P < 0.05, all scores) among GERD-FNS patients vs. GERD-NNS patients. GERD-related work loss was greater among those with GERD-FNS vs. GERD-NNS (P < 0.0001). Work loss and functional limitations were more pronounced when comparing GERD-FNS cases vs. non-GERD controls.

Conclusion

Employed adults with frequent nocturnal GERD report more severe symptoms, and are associated with impaired sleep, HRQOL and work productivity compared with controls and patients with minimal or no nocturnal symptoms.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

Gastro-oesophageal reflux disease (GERD) is a common and costly illness that significantly impairs health-related quality of life (HRQOL), particularly among individuals with nocturnal symptoms.1 In the US, 14–20% of adults suffer from GERD-related symptoms at least once weekly.2, 3 Nocturnal symptoms are common among individuals with GERD; two nationwide telephonic surveys reported that between 74% and 79% of adults with heartburn (at least once weekly) also report experiencing night-time symptoms.1, 4 Only recently it has been recognized that the burden of night-time GERD may be significantly greater compared with that of daytime GERD. Farup et al. reported that adults with nocturnal manifestations of GERD report greater HRQOL impairment than GERD patients without night-time symptoms.1

The economic burden of GERD is considerable. Annual direct costs of GERD, which include doctor visits and pharmaceutical treatment, are estimated at $9.6 billion (year 2000 US dollars).5 Indirect costs of GERD because of reduced work productivity and time off work for doctor visits may be substantially higher than direct costs.1, 5 Henke et al. found that over 40% of patients with GERD report reduced work productivity because of their symptoms and estimated the annual cost of GERD-related work loss at $948/year based on reported annual salaries averaging about $35 000.6 In a study of service industry employees involving retrospective analyses of administrative health claims data, Dean et al. found that annual indirect costs because of productivity loss exceeded the combined direct costs of medical care and pharmacy use ($5193 vs. $1736, respectively).7 While the evidence suggests that indirect costs drive the economic burden of GERD, to our knowledge no studies have evaluated the indirect cost of nocturnal GERD.

One important factor thought to contribute to work productivity loss among GERD patients is sleep impairment caused by nocturnal symptoms. It is known that insomnia results in daytime fatigue and performance deficits and has been associated with impaired work productivity.8 Sleep disruption is common among individuals with night-time GERD, and may contribute considerably to HRQOL impairment.1, 4 Forty-one percent of adults who suffer from nocturnal heartburn believe that their symptoms interfere with their ability to function at work the following day.4 However, we are unaware of any studies that have attempted to quantify the impact of nocturnal symptoms on daytime work productivity in GERD or in any other disease populations.

To better understand the productivity impact of nocturnal GERD, we used an Internet-based survey to explore differences in work productivity, sleep impairment and HRQOL among employed adults with GERD and frequent nocturnal symptoms (GERD-FNS) vs. GERD cases with minimal or no nocturnal symptoms (GERD-NNS) and vs. non-GERD controls. We hypothesized that work productivity loss would be greater among those with GERD-FNS compared with GERD-NNS cases, and that sleep impairment would be greatest among those with GERD-FNS. Furthermore, we expected that employed individuals with GERD-FNS would have worse HRQOL compared with GERD-NNS cases and non-GERD controls.

Methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

Data source

Data collection for this cross-sectional case–control study was conducted during September 2004 using an Internet-based survey conducted by Harris Interactive Service Bureau through the Harris Poll Online (HPO). Participants in HPO are recruited through telephone, postal mail, electronic mail and Internet web portal advertisements; registered members agree to be contacted for online surveys but can decline participation in any survey. Members completing HPO surveys receive compensation in the form of points redeemable for prizes; participants in the present study received incentives equivalent to roughly $5.

Study subjects

The survey was offered to a random sample of 65 001 US registrants of the HPO general membership who were at least 18 years of age and employed full time. In order to increase response rate and generalizability of data, the sample was divided into three replicates; each replicate was worked thoroughly before invitations for the next replicate were issued. All respondents were screened to determine eligibility and were included if they completed the questionnaire, reported not having worked any night-time shifts during the previous 7 days, and did not violate the sampling quotas (targets were n = 1000 for GERD cases, and n = 500 for controls).

Human subjects protection

The study protocol was reviewed by the Western Institutional Review Board (Olympia, WA) and was issued an Institution Review Board exemption.

Survey instrument

The survey was approximately 20 min in length and consisted of two components, an initial screener and the full questionnaire. Within each component, random rotations of questions, range checks and consistency checks were utilized to ensure reliability.

The opening screener consisted of 30 questions on socio-demographics and basic medical history in order to identify eligible participants and monitor the distribution of night-time and daytime symptoms among GERD cases (to assure adequate sample sizes for each subgroup). Following the screener, qualified respondents proceeded to the main body of the questionnaire, which included the following components: GERD Symptoms and Medication Questionnaire (GERD-SMQ), which assessed GERD status and GERD symptomatology; the Epworth Sleepiness Scale (ESS), which assessed daytime sleepiness; the Work Productivity and Activity Impairment questionnaire (WPAI; including general health and disease-specific versions), which assessed work productivity; and the Short Form-36 Questionnaire (SF-36), which assessed HRQOL. Other question items assessed night-time, daytime and supra-oesophageal symptoms, as well as sleep impairment and night-time medication use.

GERD Symptoms and Medication Questionnaire

The GERD-SMQ is a validated screening instrument designed to assess the frequency and severity of heartburn and acid regurgitation during the previous 12 months, and GERD medication use during the previous 6 months.9 Scores ranging from 0 to 44 and >9 indicate the presence of GERD.

Epworth Sleepiness Scale

The ESS is designed to measure daytime sleepiness (or sleep propensity) for eight situations using a 3-point scale (ranging from ‘0 – no chance of dozing’ to ‘3 – high chance of dozing’),10, 11 and has been validated among patients with various sleep disorders.12 Scores from the 8 items are summed for an aggregate value that represents the total daytime sleepiness score, ranging from 0 (no sleep propensity) to 24 (maximum sleep propensity).10, 11

Work Productivity and Activity Impairment questionnaire

We employed the general (completed by all respondents) and GERD-specific (completed by GERD cases only) versions of the widely used WPAI to assess productivity loss because of work-time missed (‘absenteeism’) and impairment while working (‘presenteeism’).13, 14 Absenteeism and presenteeism are also combined into the Work Productivity Score (WPS), which represents a measure of total work productivity loss.13 WPAI scales (presenteeism, absenteeism and WPS) are each reported as percentage productivity loss. For example, absenteeism of 5% implies that 1/20 of a respondent's total potential work-time during the previous 7 days was missed due to health issues; presenteeism of 20% suggests that the respondent was only working at 80% of their potential productivity level during the previous 7 days due to health issues; a WPS of 22% implies that 22% of total potential productivity was lost due to either absenteeism or presenteeism, or that a respondent was working at only 78% of their total potential productivity due to absenteeism and presenteeism.

Short Form-36 questionnaire

The SF3615 is a 36-item, self-administered questionnaire designed to assess HRQOL across eight domains. In addition, mental and physical composite scores can be calculated.16 Scores for each domain and summary measure range from 0 (poor HRQOL) to 100 (optimal HRQOL).

Assessment of night-time and daytime GERD symptoms

Dichotomous and Likert scale items were developed to assess the presence (yes/no scale), frequency (8-point scale ranging from ‘0 nights/days’ to ‘7 nights/days’ with symptoms) and severity (10-point scale ranging from ‘1 – very mild symptoms’ to ‘10 – very severe symptoms’) of night-time and/or daytime symptoms of GERD during the previous week.

Supra-oesophageal symptoms

Respondents were asked if during the previous week they had experienced any symptoms consistent with supra-oesophageal symptoms during the day and/or during the night. Supra-oesophageal symptoms assessed included: globus sensation (a feeling of fullness in the throat), sinus problems, frequent dry cough or throat clearing, sore throat, night-time snoring, wheezing, choking and hoarse voice. Respondents also rated the frequency (8-point scale ranging from ‘0 nights/days’ to ‘7 nights/days’ with symptoms) and severity (10-point scale ranging from ‘1 – very mild symptoms’ to ‘10 – very severe symptoms’) of these symptoms.

Assessment of sleep impairment

The frequency of GERD-related sleep impairment during the previous week was assessed using an 8-point scale (ranging from ‘0 nights/days’ to ‘7 nights/days’ with symptoms). Sleep impairment items included: not getting a good night's sleep due to symptoms; feeling tired from lack of sleep due to symptoms; waking up during the night due to symptoms; not feeling fresh or rested when waking up due to symptoms; having trouble getting to sleep due to symptoms and waking up at night due to symptoms, then having trouble falling asleep again.

Assessment of medication use at night

Items were developed to evaluate night-time GERD-related medication use. Frequency of night-time medication use was assessed using an 8-point scale (ranging from ‘0 nights’ to ‘7 nights’ taking medication during the previous 7 days). Behaviours assessed included: taking prescription and/or over-the-counter (OTC) GERD medication before going to bed to help prevent symptoms; and taking prescription and/or OTC GERD medication at night to reduce symptoms (after waking with symptoms).

Study definitions

The following definitions were used for this study: Night-time: at night while sleeping, or at night while attempting to sleep. GERD symptoms: heartburn and/or acid regurgitation (unless supra-oesophageal symptoms are specified). GERD cases: respondents who satisfied general study criteria, and satisfied GERD-SMQ criteria for GERD during the previous year (GERD-SMQ score >9), and reported experiencing either heartburn or acid regurgitation at any time during the previous week. GERD with frequent nocturnal symptoms (GERD-FNS): among GERD cases, those reporting night-time heartburn and/or acid regurgitation for at least two nights (need not be consecutive) during the previous 7 days. GERD with minimal or no nocturnal symptoms (GERD-NNS): among GERD cases, those who did not satisfy criteria for GERD-FNS. Supra-oesophageal symptoms: non-classic GERD symptoms of globus sensation (a feeling of fullness in the throat), sinus problems, frequent dry cough or throat clearing, sore throat, night-time snoring, wheezing, choking and hoarse voice.

Data management and statistical analyses

Statistical analyses were performed using the sas statistical package (SAS Version 8.2, SAS Institute, Cary, NC, USA). Primary group comparisons were GERD vs. controls, and GERD-FNS vs. GERD-NNS. Differences in mean values between study groups were evaluated using the t-test procedure, and differences in proportions were evaluated using chi-square tests. A clinically meaningful difference in mean SF-36 scores was defined as a difference ≥5 points.17, 18

To analyse productivity measures by severity, GERD-FNS and GERD-NNS groups were further stratified into mild, moderate and severe groups using respondent data from 4-items that assessed severity of both daytime and night-time heartburn and acid regurgitation (each on a 10-point Likert scale ranging from ‘1 – very mild symptoms’ to ‘10 – very severe symptoms’). For GERD-FNS cases, a maximum value from the two night-time severity ratings was used as the severity score; for GERD-NNS, the maximum value from the two daytime severity ratings was used. For each case group, respondents were classified into the following severity categories: mild,1–4 moderate5–7 and severe.8–10anova was used to test for linear trend in work productivity measures across GERD severity levels within GERD-FNS and GERD-NNS groups.

Using WPAI measures, we also estimated the number of lost hours per week by multiplying each percentage reduction by a 40-h workweek. Annual costs because of GERD-related work loss were also estimated based on the following key assumptions: (i) 1760 total work hours, based on 220 8-h workdays per year (this average value excludes weekends, holiday, vacation time, etc.) and (ii) an average compensation rate of $19.23/h, based on an annual salary of $40 000 and 2080 total paid hours (including vacation, holiday time pay).

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

Patient characteristics

Of 65 001 HPO members invited to participate in this study, 13 577 (20.9%) initiated the survey screener (screener respondents) during the 3-week fielding period. An overview of the survey recruitment process is illustrated in Figure 1. Socio-demographic data among screener respondents were comparable with statistics for the entire sample invited to participate. Among those screened, 1515 satisfied study and quota criteria and completed the questionnaire (qualified respondents); of these, 1002 met GERD-SMQ criteria for GERD, and 513 were controls. Socio-demographic data between cases and controls were generally comparable, although GERD patients were more likely to be married and to report higher incomes (Table 1). Respondents with GERD were significantly more likely to report general health conditions compared with non-GERD controls, and were more likely to have multiple conditions (Table 1). However, among those suffering from GERD, only depression was more commonly associated with GERD-FNS than with GERD-NNS (P = 0.0082).

image

Figure 1.  Overview of recruitment for survey.

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Table 1.   Socio-demographics and health conditions among qualified respondents by GERD status
 Non-GERD controls (n = 513)Participants with GERD
All GERD (n = 1002*)GERD-FNS (n = 476)GERD-NNS (n = 526)
  1. GERD, gastro-oesophageal reflux disease; GERD-FNS, GERD with frequent nocturnal symptoms; GERD-NNS, GERD with minimal or no nocturnal symptoms; GI, gastrointestinal; NERD, non-erosive reflux disease.

  2. * Four subjects initially in case group were removed due to inconsistency in their responses.

  3. † Missing race/ethnicity for 37 GERD cases and 20 non-GERD controls and income for 233 GERD cases and 85 non-GERD controls.

  4. ‡ P < 0.05 for GERD cases vs. non-GERD controls.

  5. § P < 0.05 for GERD-FNS vs. GERD-NNS cases.

Gender, n (%)
Male235 (45.8)412 (41.1)201 (42.2)211 (40.1)
Mean age, years (s.d.)43.67 (12.9)44.66 (11.3)44.58 (11.3)44.73 (11.4)
Race/ethnicity, n (%)†
White457 (92.7)916 (94.9)432 (93.7)484 (96.0)
Other36 (7.3)49 (5.1)29 (6.3)20 (4.0)
Education, n (%)
High school or less65 (12.7)125 (12.5)63 (13.2)62 (11.8)
Any college448 (87.3)877 (87.5)413 (86.8)464 (88.2)
Income, n (%)†
Less than $25 00066 (15.4)76 (9.9)‡50 (12.9)26 (6.8)§
$25 000 to $49 999165 (38.6)272 (35.4)136 (35.1)136 (35.7)
$50 000 to $99 999139 (32.4)268 (34.9)127 (32.7)141 (37.0)
$100 000 or more58 (13.6)153 (19.9)75 (19.3)78 (20.5)
Marital status, n (%)
Single245 (47.8)376 (37.5)‡170 (35.7)206 (39.1)
Married268 (52.2)626 (62.5)306 (64.3)320 (60.8)
Self-reported medical history
General health conditions, n (%)
 Allergies129 (25.2)394 (39.3)‡200 (42.0)194 (36.9)
 Anxiety30 (5.9)136 (13.6)‡68 (14.3)68 (12.9)
 Arthritis52 (10.1)200 (20.0)‡95 (20.0)105 (20.0)
 Asthma37 (7.2)131 (13.1)‡69 (14.5)62 (11.8)
 Cancer7 (1.4)9 (0.9)4 (0.8)5 (1.0)
 Chronic back pain44 (8.6)171 (17.1)‡85 (17.9)86 (16.4)
 Diabetes39 (7.6)61 (6.1)31 (6.5)30 (5.7)
 Dental erosions20 (3.9)35 (3.5)20 (4.2)15 (2.9)
 Depression48 (9.4)175 (17.5)‡99 (20.8)§76 (14.5)
 Headache/migraine47 (9.2)204 (20.4)‡108 (22.7)96 (18.3)
 Heart disease14 (2.7)47 (4.7)23 (4.8)24 (4.6)
 Hypertension98 (19.1)275 (27.5)‡129 (27.1)146 (27.8)
 Kidney disease2 (0.4)7 (0.7)2 (0.4)5 (1.0)
 Liver disease1 (0.2)3 (0.3)1 (0.2)2 (0.4)
 Lung disease2 (0.4)23 (2.3)‡12 (2.5)11 (2.1)
 Otitis media1 (0.2)8 (0.8)4 (0.8)4 (0.8)
 Repetitive strain injury or carpal tunnel syndrome13 (2.5)51 (5.1)‡23 (4.8)28 (5.3)
 Sinusitis55 (10.7)186 (18.6)‡92 (19.3)94 (17.9)
 Ulcer of the stomach or intestine3 (0.6)43 (4.3)‡24 (5.0)19 (3.6)
 None of the general health conditions listed202 (39.4)245 (24.5)‡113 (23.7)132 (25.1)
Number of general (non-GERD) health conditions, n (%)
None202 (39.4)245 (24.5)‡113 (23.7)132 (25.1)
1 to 3268 (52.2)541 (54.0)258 (54.2)283 (53.8)
4+43 (8.4)216 (21.6)105 (22.1)111 (21.1)
GERD-related diagnoses, n (%)
Barrett's oesophagitis14 (1.4)‡6 (1.3)8 (1.5)
Erosive oesophagitis20 (2.0)‡12 (2.5)8 (1.5)
GERD10 (2.0)305 (30.4)‡160 (33.6)§145 (27.6)
NERD1 (0.2)22 (2.2)‡7 (1.5)15 (2.9)
Schatzki Ring3 (0.3)2 (0.4)1 (0.2)
Peptic stricture5 (0.5)1 (0.2)4 (0.8)
None of GERD-related diagnoses listed502 (97.9)663 (66.2)‡302 (63.5)361 (68.6)
GI-related surgeries, n (%)
Antiobesity surgery3 (0.6)15 (1.5)10 (2.1)5 (1.0)
Appendectomy42 (8.2)125 (12.5)‡62 (13.0)63 (12.0)
Cholecystectomy34 (6.6)92 (9.2)49 (10.3)43 (8.2)
Nissen fundoplication12 (1.2)‡8 (1.7)4 (0.8)
Surgery for hernia30 (5.9)55 (5.5)28 (5.9)27 (5.1)
Surgery for ulcers1 (0.2)5 (0.5)4 (0.8)1 (0.2)
None of the GI-related surgeries listed415 (80.9)744 (74.3)‡346 (72.7)398 (75.7)

Frequent night-time symptoms of GERD

Among the 1002 respondents with GERD, 221 reported no night-time symptoms during the previous week, while 781 reported at least one night with symptoms. Of the 1002 individuals with symptoms, 476 met the prespecified criteria for GERD-FNS (≥2 nights with symptoms during the previous week) and 526 met criteria for GERD-NNS (including 305 GERD patients who had only one night with symptoms during the previous week). Socio-demographic data between GERD-FNS and GERD-NNS cases were generally comparable (Table 1). Among GERD-FNS and GERD-NNS patients, there were no significant differences in proportions of respondents who reported a medical diagnosis of Barrett's oesophagus, erosive oesophagitis, oesophageal stricture or with a previous gastrointestinal-related surgery (Table 1). As illustrated in Figure 2, GERD-FNS cases were less likely to have mild symptoms and more than three times more likely to have severe symptoms, compared with the GERD-NNS group (33.5% vs. 52.0% for mild, and 18.1% vs. 5.5% for severe).

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Figure 2.  Distribution of GERD-FNS and GERD-NNS cases by gastro-oesophageal reflux disease severity. GERD-FNS, GERD with frequent nocturnal symptoms; GERD-NNS, GERD with minimal or no nocturnal symptoms. *58 GERD cases w/missing severity ratings excluded from severity analyses.

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Supra-oesophageal symptoms

The majority of both daytime and night-time supra-oesophageal symptoms were reported by a greater proportion of individuals with GERD-FNS than with GERD-NNS (Table 2). Specifically, globus sensation, choking, dry cough, sore throat, night-time snoring and daytime hoarseness were all significantly more common among GERD-FNS cases compared with GERD-NNS cases (P < 0.05). Mean severity scores for all supra-oesophageal symptoms (including day and night) were worse among those with GERD-FNS compared with GERD-NNS; statistically significant differences (P < 0.05) in mean severity scores were noted for all night-time supra-oesophageal symptoms except for one (nocturnal wheezing). Similarly, when assessing severity of daytime supra-oesophageal symptoms, GERD-FNS cases had significantly more severe daytime globus sensation, dry cough, sore throat and choking compared with GERD-NNS (P < 0.05).

Table 2.   Supra-oesophageal symptoms at daytime and night-time during the previous 7 days among GERD-FNS cases vs. GERD-NNS cases
Supra-oesophageal symptoms during the previous 7 daysGERD-FNS (N = 476; %)GERD-NNS (N = 526; %)
Experienced during the nightExperienced during the dayExperienced during the nightExperienced during the day
  1. GERD, gastro-oesophageal reflux disease; GERD-FNS, GERD with frequent nocturnal symptoms; GERD-NNS, GERD with minimal or no nocturnal symptoms.

  2. P < 0.0001 for GERD-FNS vs. GERD-NNS cases.

  3. † P < 0.05 for GERD-FNS vs. GERD-NNS cases.

Feeling of fullness in the throat40.1*30.3*22.8*18.1*
Sinusitis or sinus problems51.954.047.054.6
Frequent dry cough or throat clearing49.2†49.2†39.7†39.4†
Sore throat31.5†30.7†21.3†24.3†
Snoring47.1†N/A39.7†N/A
Hoarseness in voiceN/A26.9†N/A20.9†
Wheezing17.016.214.815.0
Choking20.8†16.2*12.0†7.0*

Sleep impairment and daytime sleepiness

Overall, GERD-related sleep abnormalities were common among GERD patients (Table 3). The most common sleep complaint was waking due to symptoms, reported by 74.8% of GERD-FNS cases and 36.5% of GERD-NNS cases (GERD-related sleep complaints observed in the GERD-NNS group were due to 305 individuals with only one night of symptoms during the previous week who did not satisfy study criteria for GERD-FNS). Among those with GERD, a higher proportion reported taking medication after waking with symptoms (to reduce symptoms), compared with those who reported night-time medication use before going to bed to prevent symptoms. GERD-FNS cases were more likely to report using medications at night to prevent or to reduce nocturnal symptoms compared with GERD-NNS cases (P < 0.0001). Daytime sleepiness was greater among those with GERD-FNS vs. those with GERD-NNS (P < 0.05).

Table 3.   GERD-related sleep impairment, GERD medication use at night, and daytime sleepiness among GERD-FNS cases vs. GERD-NNS cases
 GERD-related sleep abnormalitiesMean nights with sleep abnormalities
GERD-FNS (n = 476)GERD-NNS (n = 526)GERD-FNS (n = 476)GERD-NNS (n = 526)
  1. GERD, gastro-oesophageal reflux disease; GERD-FNS, GERD with frequent nocturnal symptoms; GERD-NNS, GERD with minimal or no nocturnal symptoms; ESS, Epworth Sleepiness Scale; OTC, over the counter.

  2. P < 0.0001 for all differences in symptoms between GERD-FNS and GERD-NNS.

  3. † P < 0.05 for differences in ESS scores, GERD-FNS vs. GERD-NNS.

  4. ‡ Total ESS scores ranging from 0 (no daytime sleepiness) to 24 (maximum daytime sleepiness).

GERD-related sleep impairment among GERD-FNS and GERD-NNS cases during the previous 7 nights (%)
Symptoms prevented respondent from getting a good night's sleep70.6*32.3*1.8*0.4*
Symptoms caused respondent to feel tired from lack of sleep63.7*28.7*1.6*0.3*
Symptoms caused respondent to wake up during the night74.8*36.5*1.9*0.4*
Symptoms prevented respondent from feeling fresh or rested when waking64.5*27.9*1.7*0.3*
Respondent had trouble getting to sleep due to symptoms68.5*31.0*1.7*0.4*
Respondent woke during the night due to symptoms and had trouble falling back to sleep64.1*30.2*1.6*0.3*
GERD medication use during the previous 7 nights (%)GERD-FNS (n = 476)GERD-NNS (n = 526)
OTC or prescription to prevent GERD symptoms67.7*49.6*
OTC or prescription to reduce GERD symptoms76.1*63.6*
Daytime sleepiness
Mean total ESS score‡8.2†7.6† 

Work productivity

Work productivity was significantly worse among respondents with GERD compared with non-GERD controls (WPS, 20.9% vs. 10.2%; P < 0.001), and also among GERD-FNS cases compared with GERD-NNS cases. Cases with GERD-FNS had greater total work productivity loss due to GERD than did GERD-NNS cases (12.2% and 5.4%; P < 0.0001), the majority of which was due to impairment while working rather than actual time absent from work (Table 4). This difference in total productivity loss between GERD subgroups represents almost 2.7 h/week of additional productivity loss among those with GERD-FNS compared with productivity loss among GERD-NNS cases. Assuming an average annual salary of $40 000 (2080 total paid hours, and 1760 total work hours), this difference in total productivity loss amounts to $2302 in annual costs per individual with GERD-FNS beyond the indirect costs per GERD-NNS case.

Table 4.   GERD-specific work productivity loss among GERD-FNS cases vs. GERD-NNS cases
WPAI scaleMean percentage reductionP-value
GERD-FNS (n = 475*)GERD-NNS (n = 525*)Mean difference
  1. GERD, gastro-oesophageal reflux disease; GERD-FNS, GERD with frequent nocturnal symptoms; GERD-NNS, GERD with minimal or no nocturnal symptoms; WPS, Work Productivity Score.

  2. * Two GERD cases excluded due to missing data.

Work-time absent (absenteeism)0.70.30.40.1345
Impairment while working (productivity loss due to presenteeism)11.85.16.7<0.0001
Overall work productivity loss (WPS)12.25.46.8<0.0001

In assessing WPS by severity (Figure 3), increasing symptom severity was associated with increasing work loss among both GERD sub-groups (P < 0.0017 and P < 0.001, for test of trend by severity in GERD-FNS and GERD-NNS groups, respectively). Compared with GERD-NNS, the GERD-FNS group was associated with greater work loss in mild (P < 0.003), moderate (P < 0.003) and severe (P = N.S.) symptom strata. As illustrated in Figure 4, findings also reveal an apparent trend between GERD-specific work productivity loss and number of nights with symptoms during the previous 7 days, as we observed worsening total work loss (WPS) for each additional night with symptoms. Differences in work productivity loss were greatest between participants reporting exactly two nights with symptoms vs. those reporting exactly three nights with symptoms. Impairment in work productivity was more pronounced when comparing GERD-FNS vs. non-GERD controls [P < 0.001 for all subscales of the WPAI (general health version)].

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Figure 3.  Gastro-oesophageal reflux disease (GERD)-specific total work loss (WPS) among GERD-FNS and GERD-NNS cases, by severity of symptoms during the previous week. Sample sizes: Nighttime GERD (n = 475): *159 mild, 230 moderate, 86 severe; Daytime GERD (n = 526): *244 mild, 199 moderate, 26 severe WPS, Work Productivity Score from Work Productivity and Activity Impairment (WPAI) Questionnaire. * 58 GERD cases w/missing severity ratings excluded from severity analyses. † P=0.0017, when testing for a linear trend in WPS by GERD severity (GERD-FNS patients). ‡ P < 0.0001, when testing for a linear trend in WPS by GERD severity (GERD-NNS patients). ψ P < 0.003, for GERD-FNS vs GERD-NNS within severity stratum.

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image

Figure 4.  Short Form-36 component summary and Work Productivity Scores among gastro-oesophageal reflux disease cases (n = 1002), by number of nights with symptoms during previous week. WPS, work productivity score; WPAI, Work Productivity and Activity Impairment Questionnaire; PCS, physical component summary; MCS, mental component summary; SF-36, Short-Form-36 Questionnaire.

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Health-related quality of life

Health-related quality of life was significantly worse among those with GERD (data stratified by GERD-FNS vs. GERD-NNS in Figure 5) compared with the non-GERD group (P < 0.05 comparing GERD vs. controls for all SF-36 domains), whose mean SF-36 scores were comparable with US norms.19 Among GERD cases, scores were significantly lower among respondents with GERD-FNS vs. those with GERD-NNS (P < 0.05 for all SF-36 scores; Figure 5). The domains with the greatest discrepancy between GERD-FNS and GERD-NNS included ‘physical role functioning’ and ‘emotional role functioning’. There was an inverse relationship between SF-36 scores and increasing number of nights with symptoms from ‘none of the time’ to ‘4 or more nights with symptoms’ (Figure 4).

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Figure 5.  Short Form-36 scores among GERD-FNS cases vs. GERD-NNS cases and non-gastro-oesophageal reflux disease controls. *Difference significant at P<0.05, GERD-FNS vs. Control; † Difference significant at P<0.05, GERD-FNS vs.GERD-NNS; ‡ Clinically meaningful difference (geqslant R: gt-or-equal, slanted 5 points).

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Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

Our study has several important findings. First, work productivity was significantly worse among those with GERD-FNS compared with GERD-NNS (WPS, 12.2% vs. 5.4%; P < 0.0001). For a typical 40-h workweek, the burden of GERD-FNS as a result of GERD symptoms amounts to a weekly total work productivity loss of approximately 4.9 h vs. 2.2 h among those with GERD-NNS, for a difference of nearly 2.7 h. In assessing WPS by severity, we found that GERD-related symptom severity was strongly associated with work impairment, and that those with GERD-FNS were significantly more impaired than GERD-NNS patients within mild and moderate strata (comparison of severe GERD patients was consistent but did not reach statistical significance probably due to low number of patients with severe GERD-NNS). In addition, total work productivity worsened for each additional night of GERD symptoms from 4.5% work productivity loss among respondents reporting no nights with symptoms to 15.9% work productivity loss for those reporting four or more nights with symptoms. When applied to an employee with an average annual salary of $40 000, indirect costs due to GERD-FNS amount to $4133 annually when compared with $1831 due to GERD-NNS. This amounts to $2302 in annual costs per GERD-FNS case beyond the indirect costs per GERD-NNS case.

With a sizable proportion of GERD patients being working-age individuals, GERD-FNS may represent a significant economic burden to employers and society. Based on the work productivity losses reported among our employed population, the annual estimate of indirect costs in the US are $16.8 billion for GERD-FNS and $8.2 billion for GERD-NNS when the following are assumed: (i) there are 19 million GERD cases in the US;5 (ii) 75% of all GERD cases are working-age individuals;5 (iii) 60% of working-age individuals are actually employed19 and (vi) the ratio of GERD-FNS to GERD-NNS (as defined in our study) is 476/526.

At least three published studies have quantified work productivity loss due to GERD, and none of those studies examined differences between daytime and night-time symptoms. A recent survey of more than 1000 US employees found that total work productivity (including absenteeism and impairment while working) was reduced by an additional 10% among those with GERD when compared with non-GERD controls.7 For GERD participants, this amounted to over $5000 in annual lost productivity costs, somewhat higher than estimates from the present study ($4133 for GERD-FNS, $1831 for GERD-NNS). However, it should be noted that this previous survey employed only general health productivity measures (i.e. not specific to GERD), which may explain why those estimates are slightly higher than the annual GERD-specific costs reported here. From a study of the Swedish working population, it was reported that the GERD-specific work loss represented approximately 10.7 h lost per week due to both absence from work and diminished efficiency while at work.21 In contrast, a study of 150 GERD patients in a California Kaiser Permanente HMO reported GERD-related work productivity loss of only 3%, representing a loss of $940/year6 based on reported annual salaries averaging approximately $35 000. This was fairly comparable with results in our study, in which those with GERD-NNS had a GERD-specific work productivity loss of approximately 5%. However, work productivity loss in this Kaiser study was estimated using a structured interview rather than a standardized instrument, and the sample size of the GERD population was relatively small. Furthermore, it is unclear what proportion of subjects who participated in these studies were GERD-FNS patients.

Secondly, we found substantially greater sleep impairment among those with GERD-FNS when compared with GERD-NNS cases (P < 0.0001). Furthermore, we found that daytime sleepiness was also more pronounced among those with GERD-FNS compared with GERD-NNS cases, as demonstrated by the significantly higher mean total ESS score among the former group (P < 0.05). These results are consistent with previous findings of sleep impairment and reduced daytime functioning because of GERD-related night-time symptoms.4 It is known that the effects of partial sleep loss on daytime functioning can be cumulative.20 Hence, the negative impact of GERD-FNS on sleep during successive nights can lead to progressively higher daytime impairment, with these daytime effects compounding over time among the most symptomatic of GERD-FNS cases.

Thirdly, we found that GERD-FNS is associated with significantly worse HRQOL in every domain of the SF-36 when compared with GERD-NNS (P < 0.05 for all SF-36 scores), with clinically meaningful differences (defined as a ≥5 point difference17, 18) noted in four of eight domains. These findings are consistent with previously published studies that have found a similar impact of GERD-FNS on HRQOL.1 In particular, we found that the differences in HRQOL scores between GERD-FNS and GERD-NNS were most pronounced in the domains of physical and emotional role function, similar to findings reported by Farup et al.1 We also note that HRQOL appeared to further deteriorate with each additional night per week with symptoms. Although causality cannot be determined through a cross-sectional design, one might speculate that even partial symptom control of nocturnal symptoms can improve HRQOL.

Fourthly, in assessing supra-oesophageal symptoms potentially attributable to GERD, we observed that the proportion of GERD cases reporting supra-oesophageal symptoms was comparable with previous reports.2, 4 Additionally, our analysis revealed that supra-oesophageal symptoms were more common and more severe among participants with GERD-FNS compared with GERD-NNS cases, particularly globus sensation and choking. Furthermore, to our knowledge we are the first to report that supra-oesophageal symptoms among GERD-FNS cases were not only more common at night, but also more common during the day when compared with GERD-NNS cases. This suggests that potential acid exposure of the upper airways while supine at night may have lingering effects that persist even during the day.

There are several limitations to our study. First, our use of an Internet population and selection of well-defined symptomatic cases may limit generalizability to the entire population. However, it should be emphasized that our study was not intended to be a prevalence study, but rather to enable the quantification and subsequent comparison of work productivity loss, sleep impairment, daytime sleepiness and HRQOL impairment among employed individuals with GERD-FNS vs. GERD-NNS and vs. non-GERD controls. In addition, SF-36 scores for non-GERD controls were fairly consistent with US population norms and thus help to support the extrapolation of findings from this Internet sample. Secondly, recall and responder bias may affect interpretation of results, although we have no reason to suspect that this bias was different among the case or control groups. Thirdly, work productivity was assessed using a self-reported instrument without objective, third party validation. However, we were interested in between-group comparisons (GERD-FNS vs. GERD-NNS) and there is no reason to suspect any systematic differences in self-reporting between study groups. Fourthly, although we used the well-established generic SF-36 to measure HRQOL, the use of a GERD-specific HRQOL instrument might have been more sensitive for between-group comparisons of GERD-FNS and GERD-NNS. We selected a general tool in order to perform comparisons between cases and controls, for which a GERD-specific tool would not be appropriate. However, even with the generic instrument we were still able to find significant differences between GERD subgroups. Finally, we observed that individuals with GERD had more concurrent medical conditions than did non-GERD controls. This raises the possibility that sleep and/or HRQOL impairment in GERD sufferers may be due to a higher prevalence of comorbid conditions; for example, anxiety, chronic back pain and headache and could each conceivably contribute to sleep impairment and/or poor HRQOL. However, the prevalence of sleep complaints and HRQOL scores among respondents in our sample is similar to those reported by others,1, 4 even though our study was not intended to be a prevalence study. Furthermore, among GERD cases, we specifically stratified the aetiology of sleep disruption and work productivity loss due to health-related problems (in general) and impairment expressly due to symptoms of GERD. This allowed us to discern differences related specifically to GERD in an attempt to obviate confounding effects. Finally, except for depression, there were no differences in comorbidities between GERD-FNS and GERD-NNS cases, making between-group comparisons among these subgroups more reliable.

Despite these limitations, our study is unique in that it shows that frequent nocturnal symptoms of GERD are common among the working population and are associated with significantly reduced work productivity, sleep impairment and daytime sleepiness. This is a logical association, in which we have distinguished GERD-specific symptoms as the primary reason for sleep and productivity impairment in those patients who suffer from nocturnal symptoms at least twice weekly. The data also reveal an apparent trend between each additional night of symptoms and worsening HRQOL and WPSs. We used standardized and well-established instruments to assess work productivity, daytime sleepiness and HRQOL. Furthermore, in reporting work productivity loss, we were able to distinguish productivity impairment because of all health problems from GERD symptoms specifically, thus potentially controlling for the confounding impact of comorbidities found to be more prevalent among the GERD population.

Our study adds to the growing body of literature on the individual and societal burden of GERD by further helping to define the scope and significance of nocturnal symptoms, including their considerable economic and personal impact on work productivity, sleep and HRQOL. These findings help raise clinician awareness of the underappreciated effects of nocturnal GERD. Improved awareness and understanding of these manifestations should increase recognition of this common condition and thus help to minimize the overall burden of GERD to society.

Acknowledgement

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

This study was supported by Wyeth Pharmaceuticals, Collegeville, PA.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References
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