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Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. SUBJECTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. Acknowledgements
  9. REFERENCES

Objective

To compare quality of life in adults diagnosed with juvenile dermatomyositis (DM) with that of matched controls, and to analyze the association with other disease parameters in patients.

Methods

Thirty-nine patients with juvenile DM (ages ≥18 years) were clinically examined and compared with 39 age- and sex-matched controls. Global and health-related quality of life (HRQOL) were assessed by the Norwegian version of the Quality of Life Scale (QOLS-N) and the Short Form 36 (SF-36), respectively. For patients, disease parameters were assessed by the Disease Activity Score (DAS), Health Assessment Questionnaire (HAQ), and Myositis Damage Index (MDI).

Results

Compared to the controls, patients with juvenile DM assessed a median of 22.2 years (range 1.8–36.1 years) after disease onset had reduced HRQOL in general health (P = 0.009) measured by the SF-36. In patients, a moderate correlation was found between the physical component summary (PCS) score and the DAS (rs = −0.422) and MDI (rs = −0.381), and a strong correlation was found between the PCS score and the HAQ (rs = −0.516). There were no differences between patients and controls in the SF-36 mental component summary scores. Patients and controls had similar total scores of the QOLS-N, but differences existed within certain items.

Conclusion

Adult patients with juvenile DM had, compared to controls, reduced HRQOL in general health measured by the SF-36, but not in the other subscales of the SF-36 or in global quality of life measured by the QOLS-N. An association was found between disease parameters and reduced HRQOL in the physical domains.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. SUBJECTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. Acknowledgements
  9. REFERENCES

Juvenile dermatomyositis (DM) is a rare chronic inflammatory disease characterized by inflammation of muscles, skin, and other organs. Before the introduction of corticosteroid in the early 1960s, the mortality rate for patients with juvenile DM was approximately 30%, and many survivors were left with permanent impairment (1). The prognosis of juvenile DM has improved due to enhanced health care and medication. Nevertheless, a number of patients still develop irreversible impairment such as muscular, skeletal, and cutaneous damage, which may affect their health status (2).

A major goal in the treatment of children with juvenile DM is to ensure that the patient can grow up to have the best possible life. Patients' perceptions about their global quality of life (GQOL) and health-related quality of life (HRQOL) can provide important information about the impact of a disease on a patient's life. Such information can guide health care professionals in the care of future patients with juvenile DM and enhance their ability to promote quality of life (QOL) in such patients. Few studies have focused on QOL outcomes in adults with juvenile DM. A previous study from 27 centers in Europe and Latin America reported on 490 patients after a mean of 7.7 years of disease duration. The authors found decreased HRQOL in the physical domain and psychosocial domain in 10.5% and 12.8% of the patients, respectively (3). Another study from 37 countries reported on 272 children after a mean of 1.5 years of disease duration. These authors found children with juvenile DM to have impairment in their HRQOL, particularly in the physical domains (4). Huber et al reported on 65 patients after a median of 7.2 years of followup. They found that patients with juvenile DM had a favorable physical functional outcome measured by the Childhood Health Assessment Questionnaire, with a median score of 0 (range 0–2.50) (5).

Studies of other childhood rheumatic diseases have found patients to be at risk of unsuccessful social development, with a consequent impact on educational and vocational achievement (6–8). In patients with juvenile DM, little knowledge exists of long-term outcome in such areas (9).

The relationship between health and QOL is complex. Perceived health and QOL are not necessarily correlated. In chronic illness, perceived health can have an influence on patients' perceived QOL. This necessitates the use of GQOL and HRQOL measures in this study. GQOL reflects an individual's satisfaction with life (10, 11) and HRQOL reflects the individual's experience of their general health, such as physical, mental, and social well-being (12).

The primary objective of this study was to collect information regarding these issues from the perspective of the adult patient with juvenile DM. The following research questions are raised in this respect: 1) Does the QOL of the adult patient with juvenile DM differ from the general population? 2) Is there a relationship between HRQOL and GQOL in adult patients and the controls? 3) Is there a relationship between disease activity and GQOL and HRQOL in adults with juvenile DM? and 4) Do demographic characteristics such as education, employment, and income differ between adults with juvenile DM and the general population?

Significance & Innovations

  • Patients' perceptions about their global and health-related quality of life can provide important information about the impact of a disease on a patient's life.

  • Patients with juvenile-onset dermatomyositis have, after a median of 22.2 years from disease onset, reduced health-related quality of life in general health compared with the control group; however, mental health-related quality of life and global quality of life were comparable.

  • Reduced health-related quality of life in physical domains was associated with disease activity and damage.

SUBJECTS AND METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. SUBJECTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. Acknowledgements
  9. REFERENCES

In this study, a case–control design was undertaken. Approval was obtained from the Regional Ethics Committee for Medical Research and the Norwegian Directorate of Health. Informed consent was obtained from patients and controls in accordance with the Declaration of Helsinki.

Population.

Inclusion criteria consisted of a definite or probable diagnosis of juvenile DM when retrospectively applying the Bohan and Peter criteria (13), disease onset before age 18 years, and a minimum disease duration of 24 months from onset. This cohort is part of a retrospective inception cohort of patients diagnosed with juvenile DM between 1970 and 2006 in Norway (2); in the present study, patients ages ≥18 years were included. The patients were identified by electronic or manual search in Oslo University Hospital (OUH) medical records. This hospital is the referral center for children with rheumatic diseases in Norway and has the responsibility for the care of children with rheumatic diseases in a region comprising 55% of the Norwegian population (total population 4.7 million). All identified patients were located through the Norwegian population register. The Norwegian population register is a register of all people officially living in Norway. Departments of pediatrics and rheumatology in the other regional hospitals in Norway were also asked to identify and refer any juvenile DM patients treated during the last 10 years. Patients were informed of the purpose of the study by letter. Of the 44 patients who met the enrollment criteria, 4 had died and 1 declined inclusion. The study group therefore comprised 39 patients. Of the living identified patients, 97.5% participated.

Age- and sex-matched controls from Oslo and the neighboring county of Akershus were randomly selected from the Norwegian population register by a company with a license to conduct such selection. For each patient, a list of 8–10 controls was selected. An invitation to participate was posted to the first 39 controls on the list. If no acceptance was received, a letter was sent to the next selected control until an acceptance was forthcoming. An invitation was sent to 146 individuals. This resulted in 46 (32%) accepting the invitation to participate. Controls with a chronic illness were excluded from the study (3 controls excluded). For 4 cases there were 2 controls; the first to accept was selected. The patients resided throughout Norway, whereas the controls resided in Oslo and the neighboring county of Akershus.

Data collection and measures.

Data collection was carried out at OUH between November 2005 and May 2008 for the patients and between December 2007 and May 2009 for the control group. All study subjects answered the instrument at the same location at OUH and all patients were clinically examined by a single doctor (HS).

Demographic characteristics.

A multiple-choice questionnaire was specifically developed for the study in order to obtain demographic information such as sex, age, marital status, highest level of formal education, employment status, and annual income. Many of the questions had an additional open-response field, in case the respondent did not find a suitable alternative.

Norwegian version of the Quality of Life Scale (QOLS-N).

GQOL was measured in all study subjects using the QOLS-N, a 16-item domain-specific instrument that explores factors such as physical and material well-being; relationships with other people; participation in social, community, and civic activities; personal development; and recreation. Present level of satisfaction is rated on a 7-point scale. The total score is obtained by adding up the score on each item and can range from 16–112, with a higher score indicating a better QOL (14–16). This instrument has been used in general populations (17) and on patients with other rheumatic diseases (17, 18). Previous studies have shown satisfactory reliability and validity (15, 17, 19, 20).

Medical Outcomes Study 36-item Short Form (SF-36).

HRQOL was measured in all study subjects by the SF-36, version 1.0. The SF-36 consists of 36 questions on extensive areas of health covering 8 domains: general health, physical functioning, mental health, physical role limitations, emotional role limitations, vitality, social functioning, and bodily pain. In addition, it requests any changes in health during the past year. The score from each domain ranges from 0–100, with a higher score indicating a better HRQOL (21). The 8 domains contribute to the scoring of a physical component summary score and a mental component summary score. This instrument is used extensively in both adults with chronic illness (22, 23) and general populations (24), and been tested thoroughly for psychometric properties in several countries, including Norway (21, 23). It is recommended by the International Myositis Outcome Assessment Collaborative Study Group for use as an outcome measure for patients with juvenile DM (25).

Disease-related characteristics.

In patients with juvenile DM, disease-related characteristics included age at diagnosis, disease duration (defined as the time between diagnosis and followup), disease activity measured with the Disease Activity Score (DAS), physical disability measured with the Health Assessment Questionnaire (HAQ), disease damage measured with the Myositis Damage Index (MDI), and number of patients receiving prednisolone/disease-modifying antirheumatic drugs (DMARDs) at followup. Disease onset was defined as the time of diagnosis.

The DAS is a validated tool for global disease activity and in this study was scored by a participating physician (HS). It comprises 2 subscales reflecting skin involvement (range 0–9) and muscle weakness (range 0–11). The total score is rated from 0–20 (where 0 = no disease activity) (26).

The HAQ comprises 8 sections: dressing, rising, eating, walking, hygiene, reach, grip, and activities, each containing 2 or 3 questions. The score ranges from 0 (no difficulty) to 3 (unable to do). The score from each section is the worst (i.e., highest) score from any question within the section. The final score is the average of the 8 sections, with a score of 0 indicating no physical disability (27).

The MDI was scored by a physician (HS) and used to assess organ damage at the followup visit. It consists of 11 organ domains (including muscular, skeletal, cutaneous, gastrointestinal, pulmonary, cardiovascular, peripheral vascular, endocrine, ocular, infection, and malignancy), with each domain consisting of 1–8 items (28). The MDI total score is the outweighed sum of all scored items (where 0 = not present and 1 = present for ≥6 months), with a higher score indicating more damage.

Statistical analysis.

Statistical analyses were performed using SPSS, version 16. Descriptive statistics included the absolute frequency and percentage for categorized data, and the median, range, or SD for continuous data.

An independent-sample t-test was used to compare the mean values on 2 individual groups in normally distributed data. In skewed data, group comparison of the median scores was performed by the Wilcoxon-Mann-Whitney test. In order to adjust for multiple comparisons, a test was considered significant if the P value was less than 0.01, as opposed to the conventional 0.05. Correlation was expressed by Spearman's rank correlation coefficient (rs), since either or both of the variables were non–normally distributed. A correlation coefficient (rs) of 0–0.29 was considered weak, 0.30–0.49 was considered moderate, and 0.50–1.00 was considered strong. Pearson's chi-square and Fisher's exact tests for association were used to compare categorical data for independent groups, as appropriate.

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. SUBJECTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. Acknowledgements
  9. REFERENCES

Demographic characteristics of patients and controls.

The study population comprised 39 adult patients diagnosed with juvenile DM in childhood and 39 healthy controls (Table 1). For the patients with juvenile DM, the median age was 32.7 years (range 18.3–55.4 years). The median ages were 31.9 years (range 18.3–55.4 years) for female patients and 33.5 years (range 18.3–46.2 years) for male patients. Among the patients, 10 women (48%) were married/cohabitating and 2 were divorced, and 8 men (44%) were married/cohabitating and 1 was divorced. For the controls, a total of 10 women (48%) and 12 men (67%) were married/cohabitating and none were divorced.

Table 1. Demographic characteristics, education, occupation, and income of the patients and controls*
 Juvenile DM (n = 39)Healthy controls (n = 39)P
  • *

    Values are the number (percentage) unless otherwise indicated. One patient and 1 control worked part time in addition to receiving disability benefit, but are only labeled as receiving disability benefit. DM = dermatomyositis; NOK = Norwegian krone.

  • Determined by Pearson's chi-square test and Fisher's exact test, as appropriate.

Women21 (53.8)21 (53.8) 
Age, median (range) years32.7 (18.3–55.4)32.5 (18.2–55.5) 
Marital status   
 Married/cohabitating18 (46)22 (56)0.365
 Divorced/separated3 (8)0 (0)0.120
 Single18 (46)17 (44)0.820
Education   
 7–10 years of primary school3 (7.7)2 (5.1)0.337
 1–2 years of secondary school13 (33.3)10 (25.6)0.310
 3 years of secondary school6 (15.4)10 (25.6)0.262
 4 years or less at university11 (28.2)10 (25.6)0.799
 4 years or more at university6 (15.4)7 (18)0.761
Occupation, n3839 
 Full-time paying job20 (53)25 (64)0.307
 Full-time study8 (21)9 (23)0.830
 Part-time paying job4 (10.5)2 (5)0.325
 Unemployed2 (5)0 (0)0.240
 Disablement benefit/social benefit4 (10.5)3 (8)0.485
Annual income, n3737 
 <200,000 NOK13 (35)11 (30)0.619
 200,000–300,000 NOK12 (32.5)3 (8)0.009
 300,000–400,000 NOK10 (27)13 (35)0.451
 >400,000 NOK2 (5.5)10 (27)0.012

Education, occupation, and income.

When comparing the patients with the controls, no differences were found between educational achievements (Table 1). The number of full-time workers was also similar between the groups. However, when comparing full-time workers, the patients had lower incomes than the controls (Table 1). Twelve (32%) of the patients earned more than 300,000 Norwegian krone annually, as did 23 (62%) of the controls (P = 0.01). Among the 18 patients who did not work full time, 5 reported to have done so previously but were currently unable to do so due to their health problems. One patient reported never to have been able to work or study full time due to health problems. Two of the 20 patients who worked full time were currently on sick leave for unknown reasons. None of the controls reported being on sick leave.

Clinical characteristics.

Clinical characteristics of the patients are shown in Table 2. The median age at disease onset was 9.6 years (range 2.3–19.2 years). One patient was age 19 years 3 months at the time of diagnosis and above the age limit of 18 years, but was included since the symptoms existed 2 years before receiving the diagnosis. The median disease duration was 22.2 years (range 1.8–36.1 years), and 7 (18%) of the patients were treated with prednisolone/DMARDs. Thirty patients (77%) had a DAS score ≥3, 14 patients (36%) had an HAQ score >0, and 38 patients (97%) had an MDI score ≥1. The HAQ and MDI had a moderate correlation with age (rs = 0.345 and rs = 0.460, respectively). There was no significant association between age and DAS score (data not shown).

Table 2. Clinical characteristics of the patients (n = 39)*
Clinical variableValue
  • *

    Values are the median (range) unless otherwise indicated. DAS = Disease Activity Score (higher score indicates more disease activity); HAQ = Health Assessment Questionnaire (higher score indicates more physical disability); MDI = Myositis Damage Index (higher score indicates more damage); DMARD = disease-modifying antirheumatic drug.

  • Defined as the time of diagnosis.

  • Defined as the time between answering the questionnaire and the time of diagnosis.

Age at disease onset, years9.6 (2.3–19.2)
Disease duration at diagnosis, months5 (1–35)
Disease duration, years22.2 (1.8–36.1)
DAS score4.5 (0.0–13.0)
HAQ score0.0 (0.0–1.38)
MDI score5.0 (0.0–13.0)
Prednisolone/DMARD use, no. (%)7 (18)

HRQOL and GQOL in patients with juvenile DM versus healthy controls.

The scores from the SF-36 are detailed in Table 3. The general health subscale was lower for the juvenile DM patients than the controls. Among the patients, the physical functioning subscale was lower with increasing age (rs = −0.455). Age, however, had no impact on the scores for general health in either group. In the mental component scales, no significant differences emerged between the 2 groups.

Table 3. Health-related quality of life measured by the Short Form 36 in adults with juvenile DM and controls*
 Juvenile DM patients (n = 39)Controls (n = 39)P
  • *

    Values are the median score (range) for each domain. A higher score indicates better quality of life. DM = dermatomyositis; PCS = physical component summary; MCS = mental component summary.

  • Determined by the Wilcoxon-Mann-Whitney test.

Physical functioning95.0 (20.0–100.0)100.0 (20.0–100.0)0.011
Role physical100.0 (0.00–100.0)100.0 (0.00–100.0)0.060
Bodily pain84.0 (21.0–100.0)84.0 (31.0–100.0)0.871
General health67.0 (17.0–100.0)82.0 (20.0–80.0)0.009
PCS52.6 (26.9–61.5)56.4 (32.1–62.2)0.039
Vitality55.0 (15.0–90.0)65.0 (15.0–100.0)0.211
Social functioning100.0 (25.0–100.0)100.0 (25.0–100.0)0.711
Role emotional100.0 (0.00–100.0)100.0 (0.00–100.0)0.215
Mental health88.0 (36.0–100.0)88.0 (44.0–100.0)0.924
MCS53.0 (21.9–65.7)54.3 (18.7–62.8)0.893

There were no differences between the total score of the QOLS-N in patients versus controls (median 92.00 versus 89.00). The mean scores for men and women were also similar between the groups (data not shown). Within the individual items of the QOLS-N, patients were less satisfied with their health and personal safety (P = 0.003) than the controls. They were, however, more satisfied with their relationships with parents and relatives (P = 0.008) (Table 4).

Table 4. Scores for items of the Norwegian version of the Quality of Life Scale (score range 1–7) for juvenile DM patients and controls*
 Juvenile DM patientsControl groupP
  • *

    Values are the median (range). Higher scores indicate better quality of life. DM = dermatomyositis.

  • Determined by the Wilcoxon-Mann-Whitney test.

1. Material well-being/financial security6.0 (4.0–7.0)6.0 (4.0–7.0)0.484
2. Health and personal safety5.0 (2.0–7.0)6.0 (2.0–7.0)0.003
3. Relationship with parents/siblings/other relatives7.0 (4.0–7.0)6.0 (1.0–7.0)0.008
4. Having and raising children6.0 (2.0–7.0)6.0 (1.0–7.0)0.735
5. Relationship with spouse or significant other6.0 (4.0–7.0)6.0 (4.0–7.0)0.781
6. Relationship with friends6.0 (4.0–7.0)6.0 (4.0–7.0)0.232
7. Activities related to helping or encouraging others6.0 (4.0–7.0)6.0 (4.0–7.0)0.846
8. Activities related to local and national government5.0 (1.0–7.0)5.0 (1.0–7.0)1.000
9. Intellectual development5.0 (3.0–7.0)6.0 (2.0–7.0)0.028
10. Personal understanding6.0 (2.0–7.0)6.0 (4.0–7.0)0.983
11. Occupational role6.0 (3.0–7.0)6.0 (4.0–7.0)0.273
12. Creativity and personal expression5.0 (1.0–7.0)6.0 (1.0–7.0)0.520
13. Socializing6.0 (3.0–7.0)6.0 (4.0–7.0)0.725
14. Passive and observational activities6.0 (4.0–7.0)6.0 (4.0–7.0)0.190
15. Active and participatory recreational activities6.0 (2.0–7.0)6.0 (3.0–7.0)0.942
16. Independence7.0 (4.0–7.0)6.0 (3.0–7.0)0.793

Associations between QOL measures and other disease measures.

Weak correlations were found between subscores of the SF-36 and the total scores of the QOLS-N in the patient group, as opposed to the control group (Table 5). In the patients, associations between the SF-36 and the DAS, HAQ, and MDI were analyzed (Table 6). The DAS showed a moderate correlation with the physical functioning, role physical, and general health subscales. The HAQ had a strong correlation with the physical functioning subscale and a moderate correlation with the role physical, general health, and social functioning subscales. The MDI had a moderate correlation with the physical functioning and role physical subscales. There were only weak correlations between the QOLS-N and the DAS, HAQ, and MDI scores (data not shown). Weak associations were also found between the SF-36 and age at disease onset (data not shown). There was a moderate correlation between disease duration and physical functioning, but only weak correlations were found between disease duration and the other subscales of the SF-36 (data not shown).

Table 5. Correlation between the SF-36 and QOLS-N in adults with juvenile DM and age- and sex-matched controls*
SF-36 subscalesQOLS-N
Juvenile DM patientsControls
  • *

    Values are Spearman's rank correlation coefficients used for correlation between health-related quality of life and global quality of life. SF-36 = Short Form 36; QOLS-N = Norwegian version of the Quality of Life Scale; DM = dermatomyositis; PCS = physical component summary; MCS = mental component summary.

  • P < 0.01.

  • P < 0.001.

Physical functioning0.0540.315
Role physical0.1670.341
Bodily pain−0.0940.440
General health0.2160.351
PCS0.0970.269
Vitality0.2270.301
Social functioning0.2780.281
Role emotional0.1530.431
Mental health0.2520.587
MCS0.2500.408
Table 6. Correlation between SF-36 subscores and DAS, HAQ, and MDI scores*
SF-36 subscaleDASHAQMDI
  • *

    Values are Spearman's rank correlation coefficients used to find correlation between the SF-36 and disease activity measured by the DAS, HAQ, and MDI. SF-36 = Short Form 36; DAS = Disease Activity Score; HAQ = Health Assessment Questionnaire; MDI = Myositis Damage Index; PCS = physical component summary; MCS = mental component summary.

  • P < 0.01.

  • P < 0.001.

Physical functioning−0.484−0.735−0.479
Role physical−0.418−0.378−0.396
Bodily pain−0.146−0.234−0.225
General health−0.367−0.362−0.226
PCS−0.422−0.516−0.381
Vitality−0.35−0.091−0.052
Social functioning−0.265−0.333−0.206
Role emotional−0.220−0.277−0.234
Mental health−0.032−0.100−0.174
MCS−0.043−0.021−0.116

DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. SUBJECTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. Acknowledgements
  9. REFERENCES

In our case–control study, adult patients with juvenile-onset DM assessed a median of 22.2 years after diagnosis had comparable overall GQOL (measured by the QOLS-N) compared to the general population. They had poorer HRQOL (measured by the SF-36) in general health, but the other subscales were comparable. No significant relationships were found between HRQOL and GQOL. A correlation was found between HRQOL and disease activity, physical disability, and disease damage, but disease-related characteristics had no impact on GQOL. Patients had lower levels of income compared to the controls despite similar levels of education and occupational status.

The majority of the patients in this cohort were recruited from OUH, a referral-based center for children with rheumatic diseases in Norway. The number of patients in this cohort is relatively small, which is a limitation. However, we believe this cohort contains the majority of Norwegian adult patients with juvenile DM diagnosed between 1970 and 2006 (2). Patient characteristics in this cohort are comparable to other cohorts regarding age at diagnosis and duration from disease onset to diagnosis (2, 9). However, it cannot be ruled out that there may be patients who have not been included due to lack of contact with the departments of pediatrics and rheumatology. This could make the study biased toward more severe cases, which could have an influence on the results. Still, our study shows patients with juvenile DM to have favorable outcomes regarding QOL, despite the possibility of patients with milder cases of juvenile DM not being included.

It has been increasingly recognized that GQOL and HRQOL are important issues in order to provide a comprehensive understanding of the impact of a disease on a patient's life. We found that patients have poorer HRQOL measured by the SF-36 in general health, with a difference of 15 compared to controls. Differences in SF-36 subscales of more than 10 have been proposed to be of clinical difference when comparing normative numbers to groups with different conditions (24). It is not surprising that HRQOL of patients with juvenile DM can be affected by the disease, and the subgroups of the SF-36 enable us to evaluate which aspects of QOL are affected. General health quantifies patients' perceptions of their health (21).

Poorer physical functioning was associated with increasing age among patients with juvenile DM. An explanation for this could be that recent improvements in care and treatment have had a favorable outcome in younger patients. Another explanation could be that accumulations of damage due to years of persistent disease activity have resulted in decline of physical functioning, an explanation supported by the moderate correlation found between the MDI and physical functioning. A recent article has shown that patients in this cohort were treated less aggressively before 1990, which had a detrimental effect on other long-term outcome scores (2). The number of patients in this cohort is relatively small, and larger studies may be necessary to obtain further information regarding this finding.

Data from a Norwegian SF-36 health survey from the general Norwegian population have shown that physical health scores were reduced with increasing age (24); however, there was no correlation between age and physical functioning in the control group. An explanation for this could be that this cohort is relatively young. The median age of the control group was 32.5 years, and there was only 1 patient and 1 control age >50 years. A relatively young cohort could mean the effect of age would not yet be apparent in the healthy control group.

Results from our study indicate that a majority of the patients still have some disease activity or sequelae from the disease measured by the DAS, HAQ, and MDI. This has influenced their HRQOL, with an impact on physical functioning, role physical, general health, and social functioning. A previous article based on children and adults with juvenile DM in Norway found many patients to have muscle weakness (31–42%) and magnetic resonance imaging–detected muscle damage (51%) (29), which further support these findings. Despite this, adults with juvenile DM had similar scores to the controls in the physical functioning, role physical, bodily pain, vitality, role emotional, and mental health subscales and the summary scores of the SF-36. The patients and the controls also had similar total scores on GQOL measured by the QOLS-N, indicating that the impact of the disease on the mental health domains and GQOL is limited or it has no impact at all. Even though we found that GQOL was similar between the patients and controls, the patients were less satisfied with their health and personal safety. They were, however, more satisfied with their relationships with parents and close relatives. A study based on face-to-face interviews with adult patients with juvenile idiopathic arthritis (JIA) found the patients to have strong emotional bonds toward their parents based on the parents' involvement in the disease followup (30). Many of the patients in this study may have had similar experiences, which could explain this finding.

Several factors may contribute to good outcomes in satisfaction with life and mental health. Individuals may adapt to their situation over time and this response shift can play an important role in their perception of QOL (31, 32). Measurement of GQOL and mental health can, however, be difficult and arbitrary since individuals do not have the same frame of reference when answering a given question. Some studies have found chronic illness or health to have an impact on QOL (8, 33), whereas other studies have found that people with severe chronic illnesses have reported QOL equal or superior to healthy people (34, 35). This study has found adults with juvenile DM to be as content with their QOL measured by the QOLS-N and mental health measured by the SF-36 as healthy controls. The significant factors contributing to this finding are, however, not apparent.

This study showed weak correlations between the sum score of the QOLS-N and the SF-36 subscores among the patients, but some moderate correlations existed among the controls. Patients' adaptation to their situation could offer an explanation for this finding. Adaptation to a situation regarding health would imply that satisfaction with QOL may be less affected by health. The DAS, HAQ, and MDI scores were not associated with GQOL, indicating that poor outcome on disease activity and physical disability should not necessarily be equated with poor QOL. Findings similar to this were found in a study of patients with cystic fibrosis who, despite symptoms from a serious disease, reported having better QOL than controls (35).

Patients in this study have a similar level of education to the control group, but despite similar educational achievement, the annual income level was less for the patients than the controls. It should be noted that the controls answered the questionnaire an average of 1 year later than the patients; however, this is unlikely to account for these differences. The patients and controls were from both urban and rural areas, but were not matched based on residency location. Despite Norway being relatively uniform regarding unemployment rate and income level, we do not know if location of residency has influenced the results.

Lack of a relationship between education and income in patients with chronic illness has been demonstrated in a study of young adults with persisting absence epilepsies (36). Other studies have shown that adults with JIA are comparable to healthy controls in terms of level of education, but results on occupational outcomes have varied in different studies (8, 37). Employment status can play an important role in social integration and can be a good measure of the social consequences of juvenile DM. A study showed that 78% of patients with JIA reported the disease to have influenced their choice of occupation (6). In the present study it is unclear whether the level of education has led to employment appropriate to that level, or if the disease has influenced the choice of education and/or career. In order to help patients facing potential occupational challenges, early career advice with followup into adulthood may be an area to focus on in the future.

A limitation of this study lies within the conceptual framework of QOL and the constraints of the QOLS-N and SF-36. Although used widely, they are generic instruments that may not cover or accurately measure domains significant to adults with juvenile DM. In order to achieve a more comprehensive knowledge about QOL in juvenile DM and the multidimensional aspects that could influence QOL, further research is required.

In summary, we found that juvenile DM can have an impact on the adult patient's QOL. Adult patients with juvenile DM have reduced HRQOL after a median of 22.2 years from disease onset within general health. However, patients reported overall GQOL and mental HRQOL comparable to the control group, suggesting that patients with juvenile DM have good GQOL in adult life without long-term psychosocial effects. Hopefully further improvement in patient care and medical treatment will provide even better long-term outcomes in the future.

AUTHOR CONTRIBUTIONS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. SUBJECTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. Acknowledgements
  9. REFERENCES

All authors were involved in drafting the article or revising it critically for important intellectual content, and all authors approved the final version to be published. Dr. Tollisen had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study conception and design. Tollisen, Sanner, Flatø, Wahl.

Acquisition of data. Tollisen, Sanner, Flatø.

Analysis and interpretation of data. Tollisen, Sanner, Flatø, Wahl.

Acknowledgements

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. SUBJECTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. Acknowledgements
  9. REFERENCES

We thank Mari Vårdal for statistical advice and Torhild Garen for technical assistance.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. SUBJECTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. Acknowledgements
  9. REFERENCES