Utility of the Health Belief Model in predicting compliance of screening in patients with chronic hepatitis B

Authors


Dr C.-T. Wai, Division of Gastroenterology, Department of Medicine, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074.
E-mail: waict@nuh.com.sg

Summary

Background : Regular surveillance is recommended for patients with chronic hepatitis B, to select candidates for anti-viral therapy and detect early complications. However, factors that determine compliance are not well studied.

Aim : To determine the utility of the Health Belief Model in explaining non-compliance, among a group of chronic hepatitis B patients for screening.

Methods : A total of 192 chronic hepatitis B patients who responded to advertisement for free screening took part in a telephonic interview study. Subjects were asked about the five constructs of the Health Belief Model, and factors associated with recent screening were analysed.

Results : The mean age of the subjects was 42.1 ± 0.7 years; 77% white male, and 97% Chinese. About 108 patients (56%) had recent screening. At multivariate analysis, only the ability to remember date of follow-up (OR: 4.37; 95% CI: 2.07–9.17) and the perception of having to wait a long time for venepuncture (OR: 0.38; 95% CI: 0.19–0.79) were significantly associated with recent screening.

Conclusion : Future public health measures should include improving the logistics of follow-up procedures and providing reminders for screening to improve compliance.

Introduction

Patients with chronic hepatitis B (CHB) are at risk of developing serious complications such as cirrhosis, hepatic decompensation and hepatocellular carcinoma (HCC).1, 2 Singapore is a small nation in Southeast Asia with a population of 4 million, and is moderately endemic with hepatitis B virus (HBV) infection, with the prevalence of hepatitis B surface (HBsAg) being 4.1%.3 Hence, it is not surprising that liver cirrhosis is the 10th commonest cause of death in Singapore, and HCC is the fourth commonest cancer among Singaporean males, with an age-standardized rate of 18.9 per 100 000 person-year.4, 5

The median doubling time of HCC is estimated to be 4 months, and HCC may have a long asymptomatic stage lasting for months to years.6 Many studies have shown that HCC detected at the asymptomatic stage are associated with better patient survival than symptomatic HCC, because of higher likelihood of curative treatment.7, 8 Thus, many authorities recommend that periodic screening of patients be performed in patients with CHB, with abdominal ultrasonography and serum α-fetoprotein (AFP) assay, so as to ensure earlier detection of treatable HCC and hence, better survival.9–11

In Singapore, approximately 80% of medical care are delivered at government-subsidized primary or specialized clinics or government-run restructured hospitals, whose costs of screening, which include abdominal ultrasonography and AFP assays, are about US$38 (US$21). The remaining 20% of medical care are delivered by private general practitioners or private specialists, whose medical care are non-subsidized.

For the screening programme to be effective, the screening procedures must be acceptable to most patients with CHB, and screening visits be followed closely. However, compliance of such screening policy, and factors that affect compliance, had not been evaluated. In one 16-year follow-up study on hepatitis B screening involving 1487 patients in the USA, approximately 70% of the patients had only one AFP measurement and <50% had two measurements.12 In a similar pilot study by our group, we found that 64% of patients with CHB from the community were not on regular follow-up.13 However, no analysis has been made to determine factors associated with better compliance in either study.

The Health Belief Model (HBM) was originally designed to understand why people at risk of a disease did not participate in the disease detection programme.14 According to the HBM, a subject is more likely to take a ‘health action’ if he perceives himself: (i) susceptible to the disease; (ii) perceives the disease as serious; (iii) perceives benefits of the health action; (iv) perceives limited barriers to the health action and (v) receives a cue to take the health action. HBM had been evaluated in various cancer screening strategies such as breast and colon cancer,15–17 but its utility in HCC screening among patients at risk, i.e. patients with chronic viral hepatitis, had not been studied.

Therefore, in this study, we aim to determine factors that are related to patient compliance, as well as utility of the HBM in explaining non-compliance, among a group of patients with CHB for HCC screening. We achieved this by first recruiting a heterogeneous group of patients with CHB through advertisements, followed by conducting a telephonic interview on questions from the five constructs of the HBM.

Methods

Study subjects

A free screening programme for adult CHB patients was advertized in local newspapers in over a 4-week period. Subjects who were known to be carriers of HBV were invited to take part in a free screening programme, which included abdominal ultrasonography and AFP assay. Hepatitis B carrier status of these patients was confirmed by repeat testing of the HBsAg. The study subjects came from the community and included CHB patients who were on regular follow-up, those who had never been screened previously, as well as those who had defaulted screening. About 619 subjects responded and came forward for the free screening programme. These subjects were then re-contacted and invited to take part in this study. All subjects gave informed consent to the study. About 398 subjects could not be contacted because of incorrect contact information, of which 51 did not leave a contact telephone number behind, 98 gave the incorrect telephone number, and 249 could not be contacted despite being called three times or more by the research nurses. About 221 subjects were contacted, of which 29 refused to take part. Hence, 192 subjects were interviewed for the current study (Figure 1). A waiver for application was obtained from the Institutional Review Board of the National University Hospital but all study subjects gave informed consent before taking part in the study.

Figure 1.

Algorithm of participating subjects.

Interview and questionnaire

All subjects were interviewed through telephone using a standard questionnaire by a team of experienced, hepatology-trained, research nurses. Each interview lasted for about 20 min. The questionnaire contained questions on socio-demographic factors, as well as questions based on the five constructs of HBM: susceptibility, severity, benefits of taking action, barriers to taking action and cues to action.14

Questions on ‘severity’ asked if the subjects considered hepatitis B infection a serious disease and whether it affected their family members and their own work/social life. Questions on ‘susceptibility’ asked for subjects’ perception on their chance of developing liver disease and how often they worried about their liver disease. Questions on ‘benefits’ asked if the subjects perceived liver cirrhosis and liver cancer could be treated, and if screening could effective diagnose early complications. Questions on ‘barriers’ asked if the subjects considered screening programmes inconvenient, uncomfortable, or expensive. Questions on ‘cues’ asked if subjects could always remember their follow-up appointment, and if they had attended any recent public talks on liver disease, or read any public education materials in the mass media. Answers to the questions were given either as ‘agree/disagree/unsure’, or ‘never/sometimes/always’.

Definition of recent screening for HCC

Subjects were also asked about their last appointment with their family doctor, or gastroenterologists for the purpose of screening for HCC at either private or government-run primary care of specialized clinics. Subjects who had screening done within the past 12 months were considered to have recent HCC screening. Those who never saw a doctor for screening for HCC, or had screening done more than 12 months ago were considered not to have recent HCC screening.

Statistical analysis

Data were expressed as mean ± S.E.M. unless otherwise stated, and were analysed using the spss v. 10.0 program (SPSS Inc., Chicago, IL, USA). Univariate analysis was first performed to evaluate if any significant socio-demographic factors or answers to the questions from the five constructs of HBM, were associated with recent screening. Categorical variables were compared by chi-square test, Fisher's exact test, while continuous variables were compared by Mann–Whitney U-test, as appropriate. Factors with P < 0.10 in the univariate analysis were then analysed by multivariate analysis with backward logistic regression to identify independent factors associated with recent screening. Estimates of the multivariate adjusted odds ratios (OR) and 95% confidence intervals (CI) were then made.

Results

Characteristics of study subjects and non-study subjects

A total of 192 subjects took part in the study whereas 427 did not. Differences in patient characteristics between the two groups were shown in Table 1. Subjects whom were not contactable or refused to participate were predominantly more male by gender and younger by age. However, no difference in their baseline liver panel was noted. Other demographic characteristics such as education level, income and family history of liver diseases cannot be ascertained as they did not take part in the study.

Table 1.  Characteristics of study subjects and non-study subjects
 Study subjects (n = 192)Non-study subjects (n = 427)P-value
  1. ALP, alkaline phosphatase; ALT, alanine aminotransferase; AST, aspartate aminotransferase.

Male gender (%)148 (77)388 (91)<0.001
Age (years)42.1 ± 0.739.3 ± 0.50.001
Chinese by ethnicity (%)184 (97)408 (96)0.59
Bilirubin (μm)10.3 ± 0.410.5 ± 0.30.79
ALT (U/L)49 ± 452 ± 30.64
AST (U/L)32 ± 331 ± 10.79
ALP (U/L)73 ± 273 ± 10.93

Study subjects

The socio-demographic data of the 192 subjects were illustrated in Table 2. Age of the subjects were 42.1 ± 0.7 years, 148 (77%) were male, and 185 (97%) were Chinese by ethnicity. Sixty-seven subjects (35%) had known family history of CHB and 35 (18%) had family history of HCC. Duration of known status of being HBV carriers was 13 ± 1 years. About 164 (85%) has had screening before, either by ultrasonography or blood tests or both before, of which 108 (56%) had screening for HCC within the last 12 months and were considered to have recent screening of HCC. No difference in socio-demographic variables was noted between those with and those without recent screening.

Table 2.  Comparison between those with and without recent screening
 All patients (n = 192)Subjects with recent screening (n = 108)Subjects without recent screening (n = 84)P-value
  1. P-value indicates comparison of data between those with and without recent screening.

  2. HBV, hepatitis B virus.

Age (years)42.1 ± 0.741.7 ± 1.042.6 ± 1.00.53
Male (%)148 (77)85 (79)63 (75)0.61
Chinese (%)184 (97)103 (97)81 (98)1.00
Monthly income >S$2000116 (70)65 (70)51 (70)1.00
Monthly income >S$400045 (27)26 (28)19 (26)0.86
Highest education level (%)
 Secondary or below41 (47)22 (39)19 (61)0.96
 Tertiary109 (57)62 (57)47 (56) 
Type of housing (%)0.12
 Public housing127 (66)66 (61)61 (73) 
 Private housing65 (34)42 (39)23 (27) 
Family history of hepatitis B (%)67 (35)47 (38)26 (31)0.36
Family history of liver cancer (%)35 (18)23 (21)12 (14)0.26
Duration of known HBV carrier status (years) 13 ± 1 14 ± 112 ± 10.27

The Health Belief Model

Answers to the HBM were shown in Table 3. Between subjects who had and did not have recent HCC screening, no significant difference was seen in the constructs of ‘perceived seriousness’, ‘perceived susceptibility’ and ‘perceived benefits of action’. Significant variables were noted in the constructs of ‘barriers to action’ and ‘cue to action’. Subjects with recent screening were more likely to find screening embarrassing, and able to remember the date of the follow-up. On the contrary, they were also less likely to find screening uncomfortable, and less likely to perceive having to wait for long time to have their blood taken, or to see their doctors.

Table 3.  Answers to the questions on the Health Belief Model (HBM)
Components of the HBMSubjects with recent screening, n (%) (total = 108)Subjects without recent screening, n (%) (total = 84)P-value
  1. P-value indicates comparison of data between those with and without recent screening.

Perceived seriousness
 Liver disease is a serious disease
  Agree105 (97)81 (97)0.53
  Disagree or unsure3 (3)3 (3) 
 Liver disease would affect my family members
  Agree90 (83)70 (83)0.58
  Disagree or unsure18 (17)14 (17) 
 Liver disease would affect my work/social life
  Agree84 (78)68 (81)0.36
  Disagree or unsure24 (22)16 (19) 
Perceived susceptibility
 What is your chance of developing liver disease?
  Very high32 (30)29 (35)0.29
  Don't know, maybe, or not at all76 (70)55 (65) 
 How often do you worry about getting liver disease?
  Never38 (35)34 (41)0.27
  Always or sometimes70 (65)50 (59) 
Perceived benefits of action
 Liver cancer cannot be treated
  Disagree43 (40)37 (44)0.35
  Agree or unsure65 (60)47 (56) 
 Liver cirrhosis cannot be treated
  Disagree44 (41)30 (36)0.29
  Agree or unsure64 (59)54 (64) 
 Regular screening with ultrasound and blood tests is effective in detecting liver disease at an early stage
  Agree103 (95)78 (93)0.33
  Disagree or unsure5 (5)6 (7) 
Perceived barriers to action
 I rather not know if I had liver disease
  Agree8 (7)10 (12)0.18
  Disagree or unsure94 (93)74 (88) 
 Regular screening with ultrasound and blood tests is safe
  Agree100 (93)78 (93)0.59
  Disagree or unsure8 (7)6 (7) 
 Screening is expensive
  Agree59 (55)57 (68)0.087
  Disagree or unsure49 (45)27 (32) 
 Screening is uncomfortable
  Agree4 (4)17 (20)<0.001
  Disagree or unsure104 (96)67 (80) 
 Screening is embarrassing
  Agree9 (8)1 (1)0.025
  Disagree or unsure99 (92)83 (99) 
 It is inconvenient for me to come to see doctor
  Agree36 (33)30 (36)0.42
  Disagree or unsure72 (67)54 (64) 
 I waited too long for the ultrasound
  Agree29 (27)29 (35)0.16
  Disagree or unsure79 (73)55 (65) 
 I waited too long for the blood test
  Agree21 (19)28 (33)0.043
  Disagree or unsure87 (81)56 (67) 
 I waited too long to see doctor
  Agree32 (30)36 (43)0.080
  Disagree or unsure76 (70)48 (57) 
 I am anxious of finding out what disease I may have
  Agree60 (56)54 (64)0.28
  Disagree or unsure48 (44)30 (36) 
Cue for action
 I always remember date of my follow-up
  Agree95 (88)52 (62)<0.001
  Disagree or unsure13 (12)32 (38) 
 I have attended a public talk on liver disease over the last 12 months
  Agree11 (10)7 (8)0.43
  Disagree or unsure97 (90)77 (92) 
 I have read some materials on TV or newspaper on liver disease over the last 12 months
  Agree75 (59)53 (63)0.22
  Disagree or unsure33 (41)31 (37) 

Independent factors associated with recent HCC screening

As the variables in the HBM are interrelated, multivariate analysis was performed to identify independent variables associated with recent screening. Factors with P < 0.01 from univariate analysis were analysed by multivariate analysis by backward logistic regression. Only the ability to remember date of follow-up (OR: 4.37; 95% CI: 2.07–9.17), and perception of having to wait long for blood test (OR: 0.38; 95% CI: 0.19–0.79), were independently associated with recent screening.

Discussion

Unlike other chronic liver diseases such as chronic hepatitis C, metabolic and autoimmune liver diseases, where HCC occurs primarily in those with liver cirrhosis, HCC can occur in HBV carriers in the precirrhotic stage.9, 10 This makes the seemingly ‘healthy HBV carriers’ targets of HCC screening. It is partly for this reason that the term ‘healthy HBV carriers had been replaced by either ‘immunotolerant phase’ or ‘inactive carriers’, which indicate absence of significant liver inflammation, but with possibility of deterioration or development of complications in future.9, 10 As most patients with CHB feel well, it becomes difficult to persuade them to come for regular surveillance, which usually includes 6–12 monthly abdominal ultrasonography and AFP assay. In fact, our pilot study showed that up to two-third of carriers of HBV in the community were not on regular follow-up.13 Results from our pilot study, together with our anecdotal clinical experience, prompted us to undertake the current study to evaluate factors associated with compliance of surveillance, which may lead to earlier diagnosis for HCC and hence, better HCC cure rate and patient survival.

Our study is unique in several ways. To begin, both subjects with or without recent screening or regular follow-up, were included in the study. This allows us to evaluate variables associated with recent screening. Secondly, to the best of our knowledge, although HBM had been used to account for compliance for screening and surveillance for common cancers such as breast and colon cancer,15–17 as well as other chronic illnesses like diabetes mellitus,18 HBM had not been evaluated in patients at risk of HCC. Our study showed that some of the variables in the constructs of perceived barriers to action, and cue to action, were significantly related to recent screening among a heterogeneous group of CHB patients. Although our study is pilot in nature and our results ought to be confirmed by larger community studies, our results provided means by which public health officials could employ in improving compliance for surveillance among high-risk individuals for HCC.

In this study, 84 of 192 (44%) of the study subjects who responded to our advertisement have not had screening over the last 12 months. This high rate of non-compliance is similar to results of our pilot study (64%).13 This is of great public health concern as these patients may present late with complications of cirrhosis or HCC, which may reduce their success rate of cure, as well as increase mortality and morbidity.8

To our surprise, none of the socio-demographic factors such as age, family history of CHB or HCC, monthly income and education level, was associated with recent screening. In fact, the only two independent variables were waiting time for taking blood, and ability to remember date of follow-up. Our results implied that streamlining logistics of screening procedures like venepuncture, and providing reminders to patients on their follow-up dates, may be more important than public health education. Under the current system in Singapore, patients with CHB first have to visit the clinics 1–2 weeks before the actual appointment for venepuncture and ultrasonography of the upper abdomen. On the actual appointment date, the primary care doctor or hepatologist would then review the results and discuss progress with the patients. Venepuncture is performed by clinic nurses, and waiting time before blood taking is variable and depends on number of nurses available and number of patients in the queue. Besides, no government-run primary care clinics or specialist clinics provides a reminder to inform patients of their next follow-up appointments, or do they provide a reminder for patients who miss their appointments. As HBV carriers are often reviewed 6–12 monthly, a previsit reminder to follow-up, as well as a postvisit reminder for defaulted patients, may help increase the compliance rate.

Health Belief Model has been evaluated in colon and breast screening programmes. Umeh and Rogan-Gibson interviewed 178 asymptomatic young British women on breast self-examination, and showed that perceived severity and barriers were predictors of compliance.15 Harewood et al.16 interviewed 300 attendees to a tertiary gastroenterology clinic, who were aged 50–80 years, on the domains of the HBM on colon cancer screening, and found that barriers such as bowel preparation, embarrassment and afraid of discomfort, were among the commonest reasons deterring them from screening colonoscopy. Summing up these studies, overcoming barriers appears to be an important aspect of improving compliance among asymptomatic high-risk subjects to undergo cancer screening.

We acknowledge limitations of our study. To begin with, we only surveyed HBV carriers who wanted to have a free screening for their hepatitis B status, and hence, our study population may not represent all CHB patients in the community. On one hand, HBV patients who have been on regular follow-up with their own doctors may not have responded to the advertisement. On the other hand, subjects who responded to our advertisement may be more conscious of their health with better compliance rate. However, to overcome this limitation, we ought to perform a large-scale population survey for better sampling, which would be logistically difficult to perform. Secondly, Singapore is a developed country with a heavily subsidized public health care system, so results of this study may not be representative for other communities, where education level and health care system differ. Thirdly, although we find waiting time for blood tests, and ability to remember date of follow-up visits, were associated with compliance of screening, it remains to be tested if improvement in these two aspects would truly improve the rate of compliance of follow-up. However, we believe our results pointed out interesting and previously unrecognized areas for improvement for follow-up of patients with CHB.

In addition, while mode of acquisition through injection drug use, history of substance abuse, adverse effects from treatment have been found to be associated with higher rate of non-compliance in follow-up and treatment in patients with chronic hepatitis C, these factors were not evaluated in this study.19, 20 However, majority of Asians including our patients presumably acquired CHB through vertical transmission, it would be difficult to asses if the mode of acquisition affects compliance in patients with CHB. Besides, substance abuse is rare in Singapore, and no anti-viral therapy has been given to majority of patients in this study.21

Lastly, we only managed to interview 192 (31%) of the original 619 subjects. This is because this interview is a recall from the original screening exercise. In the original programme, subjects underwent blood testing and ultrasonography of the upper abdomen as a screening exercise, and many did not leave behind their contact number, making it difficult to re-contact them for this study. Although the 192 study subjects and the 427 non-study subjects were similar in their liver panel results, we were not able to compare other demographic factors such as education level, income, family history of liver disease, etc. This could potentially cause bias in the analysis. Interestingly, about two-thirds of the originally screened population could not be re-contacted, including the 149 subjects without correct contact information and the 249 subjects who could not be contacted despite repeated calling. While reason for the failure of recall is uncertain, this poses an extra barrier to the current screening system.

In conclusion, we found that 44% of the interviewed patients with CHB have not had screening over the last 12 months, which is an area of public health concern. HBV carriers with recent screening were less likely to find waiting time for blood taking long, and more likely to remember their date of follow-up visits. Proper streamlining of logistics at clinics, and providing pre- and post-follow-up visit reminders, may help improve patients compliance rate for screening.

Acknowledgement

No financial assistance was received for this study.

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