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Keywords:

  • Rheumatoid arthritis;
  • Employment;
  • Work disability;
  • Labor force participation

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES

Objective

To evaluate labor force characteristics among patients with rheumatoid arthritis (RA) in Lithuania. To assess if Lithuania's transition from a state-planned to a free-market economy after 1990 changed the employment perspectives of patients with RA.

Methods

RA patients, age 16–65 years (n = 238), were randomly selected from the RA register in Vilnius. They completed questions about sociodemographics, working status, and disease characteristics, they underwent a clinical examination, and they completed the modified Health Assessment Questionnaire and the Short Form 36.

Results

Age- and sex-adjusted employment was 24.2% lower and work disability 51.7% higher in patients compared with the general population in Lithuania. After 10 years of disease, 48% of the patients had withdrawn from the labor force. In those with a paid job, the average sick leave in the past year was 31.9 days compared with the national average of 10.8 days. Although disease activity was not significantly different in employed compared with work-disabled patients, physical function and perceived quality of life (except general health) were worse among patients with work disability. The change in economic organization in 1990 was noted to increase the risk for work withdrawal by a factor of 2.75 (95% confidence interval 1.68–4.53).

Conclusion

In Lithuania, the impact of RA on work disability is important. Although work disability in Lithuanian patients with RA seems more pronounced compared with reports from Western societies, variables associated with work disability are comparable. The transition to a market-orientated economy in 1990 increased the risk of becoming work disabled.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES

Labor force participation (LFP) is recognized as an important outcome measure when assessing the impact of rheumatoid arthritis (RA) (1). An increasing number of studies on this issue have been published over the past years (2–5). Different consequences of the inability to perform paid work have been explored, including loss of social contacts resulting in reduction of quality of life and lower self esteem (6). All these studies on LFP in RA, except for 1 from Slovakia in 1984 (7), were performed in the United States and in Western European countries having high employment rates, high quality of health care provision, and stable social security systems. Because differences in labor market conditions and social security systems are likely to influence the possibilities for LFP, the data from these studies cannot be extrapolated to Eastern European countries. No data have been published from this geographic region in recent years, during which major economic processes of decentralization and privatization took place. Employment in people with RA or ankylosing spondylitis was recently shown to be significantly lower under less favorable labor market conditions in a study comparing former East and West German states (5). Previously, we showed that patients with RA in Lithuania had worse physical function and higher disease activity when compared with age- and sex-matched patients with RA in Norway (8). In the present study, we extensively evaluated working status in patients with RA in Lithuania; characteristics of those who are work disabled were compared with those who are employed; and the associations with quality of life were estimated. In addition, the influence of the transition to a free-market economy in 1990 on LFP was analyzed.

PATIENTS AND METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES

Patients.

Patients were selected from the RA register of Vilnius, the capital of Lithuania. The register was established in 1998 and included 1,018 patients with RA for 486,500 adult inhabitants of Vilnius. Criteria for enrollment include a diagnosis of RA according to the American College of Rheumatology (formerly American Rheumatism Association) 1987 revised criteria for RA (9) and a residential address in Vilnius. All patients with RA are enrolled in 1 of the 14 outpatient clinics and are recorded to the register once per year by their general physician or rheumatologist (8). Because of the differences in access to rheumatologic care in different outpatient clinics, a random sample of 10 of 14 outpatient clinics was selected to participate. A total of 736 patients were registered with RA and 700 (from 36 the exact address could not be retrieved) were invited for interview followed by the clinical examination. Questions on labor force characteristics were completed only by patients aged 16–65 years.

Data collection.

Data were collected by a structured interview performed by 1 nurse, questionnaires completed by the patient, and a clinical examination performed by a rheumatologist (SS). The interview comprised sociodemographic questions including age, sex, years of formal education and the highest completed education level, profession, occupation at present or the last work (dichotomized into manual opposed to nonmanual jobs), current and past LFP, and days absent from work during the last year in those with a paid job. In addition, a visual analog scale (VAS) for pain in the last 4 weeks (0–10; higher values indicating more pain) as well as a VAS for patient's global disease assessment over the past 4 weeks (0–10; higher values indicating worse global condition) were completed. Finally, patients were asked to fill in the modified Health Assessment Questionnaire (MHAQ), measuring physical function (10), and the Short Form 36 (SF-36), measuring generic quality of life (11). Both the MHAQ and SF-36 have been translated from English to Lithuanian, back translated, and adapted if necessary according to guidelines for cross-cultural adaptation of health status and quality of life measures (12). During the clinical examination, grip strength, 28 painful and 28 swollen joint count, and the physician global assessment (1–5; higher values indicating worse condition) were determined and the last value of the erythrocyte sedimentation rate (ESR) was obtained from the records. Using the patients' global assessment, joint counts, and ESR, we calculated the Disease Activity Score in 28 joints (DAS-28), a validated index to measure disease activity (13). In this continuous scale, values <2.4 refer to a state of low disease activity and values >3.7 refer to high disease activity.

Definitions of current social status.

Work refers to the ability to perform paid work. Full-time work was defined as working 32 hours per week or more. Permanent work disability is defined as an official recognized work disability under the Lithuanian social security system. Early retirement applies to those who left the job because of age-related pension before the age of 65. Unemployment refers to those who are willing to be engaged in paid work but find no job and at the same time have no official work disability. Sick leave applies to those with a paid job and refers to absence from work because of disease. A distinction was made between RA-related and non–RA-related sick leave.

Short description of the social security system in Lithuania.

For subjects with official paid work, the Lithuanian social security system provides benefits in case of sick leave, work disability, unemployment, and early retirement. Sick leave can last 30 uninterrupted calendar days, or 150 interrupted calendar days per year. For the first 2 days, the employer pays the sickness benefit, which is 80–100% of the salary. After that period, the State Social Insurance Fund continues to pay the sickness benefit at the same level. When the sick leave reaches its maximum length, the patients are advised to see the State Medical Board of Social Expertise, where the patient is either recommended to extend the term of his sick leave or is advised to be included in the register of disabled. Depending on the severity of the medical restrictions, 3 categories of work disability can be granted, each associated with a specific disability benefit. In category I, subjects are considered fully work disabled and cannot continue in a paid job. In category II and category III, subjects are considered to be partially work disabled and can continue in an official (part-time) job. The disability pension in Lithuania consists of 2 parts: a minimal income, which is nationally stipulated, and a supplementary benefit. Patients in category I of work disability receive 1.5 times the minimal income. Patients in category II receive the minimal income and those in category III receive 50% of the minimal income. In 1999, the minimal income was set at 46 Euros per month. The supplementary part of the disability pension is calculated taking into account the number of years employed, the coefficient of the person's income under insurance, and the country's average amount of monthly income under insurance. Disability pension for a full-time working teacher with 10 years of employment and a monthly wage of 267 Euros, while moving to category II of disability pension, would be 89 Euros per month.

From 1990 onwards, revolutionary changes in state policy and economy took place in Lithuania. Command economics (propagated for many years) and centralized control methods were replaced by a market-oriented economy. Thus, while the changes were beneficial in some industries, the social and health care systems, which depend on state resources, were condemned to marginal existence. Also the changing requirements in the labor market resulted in evolved unemployment figures, failing to offer working positions to less-educated people and, probably, to people with chronic illness.

Data from the general Lithuanian population.

Data on sociodemographic characteristics, social status, and working status of the Lithuanian population were retrieved from Statistic of Lithuania 1999 (14). Data for employment, but not for work disability and sick leave population, were available for men and women separately and for different age categories.

Statistical analysis.

Employment, work disability, and type of job were adjusted by direct standardization for age and sex. Direct standardization was chosen because data necessary for indirect standardization (work disability from the general population stratified by age and sex) were lacking. The 95% confidence intervals (95% CIs) of the adjusted ratios were calculated. To compare the characteristics among the 3 distinguished categories of working status, chi-square was used for proportions and analysis of variance with Bonferonni post-hoc analysis was used for continuous variables. A Kaplan-Meier survival curve analyzed the time until withdrawal from work due to work disability in those with a paid job at onset of disease. To assess the influence of the change from state-control to free-market economy, a time-dependent Cox regression with 1990 as a time-dependent covariate was computed. In addition, the survival curves showing one group diagnosed with RA before 1990 and the other group diagnosed after 1990 (the group diagnosed before 1990 was censored at 1990) were computed and compared with a log rank. An Excel® (Microsoft, Redmond, WA) work sheet was used for direct standardization. All other analyzes were performed using SPSS/PC software version 8.0 (Chicago, IL).

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES

Patient characteristics.

Of the 700 patients invited, 404 consented to participate (response rate 58%). Of these, 238 were between the ages of 16 and 65 years and constituted the study population for this analysis. Participants did not differ in mean ± SD age (52.2 ± 9.6 versus 54.7 ± 12.8 years), sex (85.7% female versus 80.2%), or disease duration (10.4 ± 8.6 versus 12.0 ± 9.3 years) when compared with nonparticipants. Table 1 shows the sociodemographic characteristics of the patients, separated by sex. It is of note that female patients more often completed university education and were more often engaged in nonmanual jobs. The age- and sex-adjusted rate for having a manual job was 38.7% in comparison with 51.5% in the general population.

Table 1. Baseline characteristics of rheumatoid arthritis patients*
 Total (n = 238)Women (n = 204)Men (n = 34)
  • *

    Data given as mean ± SD (range) for continuous variables and no. (%) for dichotomous variables.

  • Adjusted for age and sex with the Lithuanian population.

Age, years52.2 ± 9.6 (20–64)52.0 ± 10.053.6 ± 7.0
Disease duration, years10.4 ± 8.6 (0–48)10.8 ± 8.77.9 ± 7.4
Education, years13.1 ± 3.4 (4–21)13.1 ± 3.512.9 ± 3.4
Education completed   
 University58 (24.4)51 (25.0)7 (20.6)
 Higher nonuniversity85 (35.7)73 (35.8)12 (35.3)
 As high as secondary95 (39.9)80 (39.2)15 (44.1)
Profession   
 Nonmanual profession156 (65.6)145 (71.1)11 (32.4)
 Manual professions63 (26.5)41 (20.1)22 (64.7)
 Without profession19 (8.0)18 (8.8)1 (2.9)
Manual job (in current or last position)82 (38.7)60 (18.3)22 (76.5)

Current labor force characteristics of RA patients.

Table 2 shows that 88 patients with RA (37.0%) were engaged in a paid job at the time of the study. Female patients more frequently were working than male patients. Of those who were working, 59 (71.1%) had a full-time job (70.3% female and 77.8% male patients) and 28.9% had a part-time job, compared with 8.8% part-time employees from the Lithuanian general population. Of 149 patients with full or partial work disability, 95.1% female and 85.7% male patients reported RA as the cause of their disability. Table 3 presents the adjusted figures of employment and work disability in patients and the reference figures from the general Lithuanian population. When compared with the general population, employment was 24.2% lower and work disability 51.7% higher than expected. The discrepancy between the more important increase in work disability compared with the decrease in employment can partly be explained by the possibility of having a partial work disability while continuing in a part-time job. Overall, 29 (33%) of those having a paid job had a partial work disability.

Table 2. Current labor force characteristics of rheumatoid arthritis patients*
 Total (n = 238)Women (n = 204)Men (n = 34)
  • *

    Data given as no. (%).

Work and no work disability59 (24.8)51 (25.0)8 (23.5)
Work and work disability29 (12.2)27 (13.4)2 (5.9)
Work disability; no paid job120 (50.4)100 (49.0)20 (58.8)
Unemployed8 (3.4)7 (3.4)1 (2.9)
Early retirement17 (7.1)14 (6.9)3 (8.8)
House wife3 (1.3)3 (1.5)0
Students2 (0.8)2 (1.0)0
Table 3. Employment and work disability among patients with rheumatoid arthritis by sex and age category in comparison with the general population*
Age, yearsEmploymentWork disability
TotalWomenMenTotalWomenMen
  • *

    Data presented as percentage in study group (percentage in Vilnius population). 95% CI = 95% confidence interval.

  • Data from Lithuanian general population not available for age and sex categories.

  • Significant between study group and general Vilnius population at P < 0.05 level.

  • §

    Data adjusted for age and sex to population.

20–24- (53.2)- (47.5)- (58.8)---
25–2975.0 (79.5)75.0 (75.3)- (83.6)12.512.5-
30–3440.0 (79.7)40.0 (80.0)- (79.5)8080-
35–3957.1 (85.3)57.1 (87.1)0 (83.4)5042.9100
40–4475.0 (81.7)71.4 (80.5)100 (83.0)41.742.933.3
45–4952.2 (83.0)61.1 (84.8)20 (80.9)56.55080.0
50–5440.4 (80.0)46.2 (76.9)12.5 (83.6)68.166.675.0
55–5926.7 (59.1)25.5 (47.3)33.3 (73.9)78.380.466.6
60–6418.3 (24.1)17.3 (15.0)25.0 (36.6)63.365.450
Total37.0 (65.2)38.2 (61.9)29.4 (68.8)62.6 (3.6)62.364.7
Adjusted total§41.045.832.255.327.869.9
95% CI34.6–7.438.8–52.816.2–8.248.9–61.821.5–34.047.7–79.3
Difference with population, %−24.2−36.6−16.1+51.7  

Of all 238 patients, at least 204 had a paid job before onset of RA. As can be seen in the Kaplan-Meier survival curve (Figure 1), 16% had withdrawn after 1 year of disease, 30% after 5 years, 48% after 10 years, and 72% after 20 years.

thumbnail image

Figure 1. Proportion without work disability during the course of disease among 204 rheumatoid arthritis patients employed before disease.

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Sick leave.

Of the 88 with a paid job, 50% reported at least 1 episode of sick leave during the year preceding the survey. In 72.7% of patients, sick leave was attributed exclusively to RA, in 15.9% sick leave was attributed to non–RA-related illness, and in 11.4% of patients there were RA-related as well as non–RA-related sick leave days. Averaged over all working patients, sick leave was 31.9 ± 28.2 days per year compared with the national average of 10.8 days sick leave in working subjects. Duration of sick leave for exclusively RA-related and non–RA-related causes was not different, 30.2 ± 28.4 and 29.3 ± 28.8, respectively. The length of the sick leave for those who incurred both RA-related as well as non—RA-related sick leave was almost twice as long, being 46.4 ± 23.2 days per patient.

Variables associated with work disability.

Table 4 compares sociodemographic and disease-related characteristics among patients with different working statuses. Interestingly, the DAS-28 was similar among the groups, whereas measures of physical function were worse in those who were work disabled. Patients with work disability reported significantly lower quality of life for all domains of the SF-36, except for general health. In post-hoc analysis, physical functioning was significantly different between all paired groups. Time-dependent Cox regression analysis showed a significant increase in the risk for work disability after 1990 by a factor of 2.75 (95% CI 1.68–-4.53, P = 0.001). Figure 2 illustrates withdrawal from the labor force due to work disability in patients diagnosed with RA before 1990 and after 1990 (censored at 1990). The mean time working until withdrawal from work of 94 patients diagnosed before 1990 (and censored at 1990) is 13 years (median 10 years) opposed to 9 years (median 8 years) for 110 patients diagnosed after 1990. The log rank test of these 2 groups was not significant, implying that the risk of becoming work disabled after 1990 was increased in newly diagnosed RA patients as well as in patients with already diagnosed RA.

Table 4. The demographic, disease, and quality of life characteristics of working, working with work disability, and not working but disabled Lithuanian rheumatoid arthritis patients under the age of 65 years*
 Working (n = 59)Working with work disability (n = 29)Work disability and no work (n = 120)P
  • *

    Data presented as mean ± SD unless otherwise noted. VAS = visual analog scale; 28 SJC = swollen joint count in 28 joints; 28 TJC = tender joint count in 28 joints; DAS-28 = Disease Activity Score in 28 joints; MHAQ = modified Health Assessment Questionnaire; SF-36 = Short Form 36.

  • Chi-square for proportions and F ratio by one-way analysis of variance for continues values.

Female, no. (%)51 (86.4)27 (93.1)100 (83.3)0.40
Age, years48.3 ± 10.249.1 ± 8.655.1 ± 7.0<0.001
University education, no. (%)24 (40.7)11 (37.9)19 (15.8)<0.001
Manual workers, no. (%)12 (20.3)8 (27.6)53 (44.2)0.01
Education, years14.8 ± 3.114.0 ± 3.012.2 ± 3.3<0.001
Disease duration, years8.2 ± 8.89.4 ± 9.012.2 ± 8.40.01
Pain VAS, 1–104.6 ± 1.96.4 ± 1.76.3 ± 2.0<0.001
Patient's global, 1–105.4 ± 1.85.7 ± 2.06.2 ± 2.10.05
Physician's global, 1–52.6 ± 0.92.8 ± 0.63.1 ± 0.8<0.001
28 SJC6.2 ± 6.96.5 ± 6.85.4 ± 6.20.61
28 TJC14.2 ± 9.616.6 ± 9.113.9 ± 8.70.35
Grip strength, right hand97.9 ± 40.786.7 ± 31.870.9 ± 35.9<0.001
DAS-285.5 ± 1.35.9 ± 1.15.7 ± 1.20.53
MHAQ, 0–30.8 ± 0.61.2 ± 0.61.6 ± 0.7<0.001
SF-36    
 Physical functioning58.8 ± 21.241.2 ± 22.131.4 ± 22.0<0.001
 Role physical40.7 ± 39.935.3 ± 41.58.8 ± 22.6<0.001
 Bodily pain52.0 ± 19.343.4 ± 20.036.9 ± 19.5<0.001
 General health30.5 ± 15.724.0 ± 13.526.5 ± 45.10.68
 Vitality56.7 ± 22.847.2 ± 23.341.3 ± 23.0<0.001
 Social functioning72.9 ± 25.059.9 ± 23.559.7 ± 26.70.005
 Role emotional59.3 ± 42.554.0 ± 44.034.2 ± 44.0<0.001
 Mental health64.5 ± 20.259.4 ± 19.354.1 ± 21.90.009
thumbnail image

Figure 2. Proportion without work disability in 110 rheumatoid arthritis (RA) patients diagnosed after 1990 in comparison with 94 RA patients diagnosed before 1990.

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DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES

Our study is the first to investigate LFP in RA in 1 of the former socialistic East European countries having experienced important economic changes during the last decade. All other studies on LFP in RA examined North American or Western European communities. Cross-sectional employment in these countries ranged from 42% in a publication from 1995 (15) to 61% in a publication from 2000 (4). In longitudinal studies of RA patients, an employment rate of only 36% of initially employed patients was reported in 1987 from a Finnish inception cohort after 8 years of followup (16), compared with a favorable employment rate of 58% in 1998 in a study from the US after 7 years of followup (17) and 60% in a recent publication from the UK after 5 years (18). Data on prevalent work disability range from 48% to 63%, higher figures being noted in later reports (15, 19, 20). Longitudinal studies showed that ∼30% of the patients had become work disabled in the first 2 years of disease (2); another publication found 44% had become work disabled after 10 years, with the most important withdrawal in the first 2 years (21, 22). Overall, the employment perspectives of patients with RA certainly did not improve over time. This was also clearly shown in a study by Barrett et al (2) who compared 2 matched cohorts of patients with 4-years' interval and showed the work disability rates to be higher in later cohort.

Within the limits of comparability of studies on LFP, the impact of RA on work status is more pronounced in Lithuania. The unfavorable result could be partly explained by differences in health care provision, resulting in more severe disease, but also in organization of the social security system (8). The influence of the labor market was already shown by Zink et al (5), demonstrating an adjusted risk ratio of 2.38 for premature termination of employment among patients from the former East German states when compared with patients from the former West German states. At the time of this study, unemployment was 20% and 11% in these regions, respectively. Our study is the first to describe the direct influence of economy transition on work disability, with an increase in the risk by 2.75. The exact figures for unemployment rate in years before economy transition in Lithuania are not available, but it is known that during the period 1994–1999 it increased 1.5 times and was 16.7% at the time of the study. This previously overlooked factor might apply to several countries and should not be neglected by health professionals and policy makers when planning scenarios for health care provision.

Absence at paid work has not yet received much attention in the literature (7, 23). This is surprising because sick leave is often the forerunner of permanent work disability. Mau et al (23) reported 76% of RA patients with early disease took sick leave and the length of sick leave was 5 times longer when compared with data from a health insurance register. In our study among patients with longer disease duration, the average number of days of sick leave was somewhat more favorable, probably because patients with the most severe disease had already left the labor force because of work disability.

When studying the determinants of LFP, our results fit well with the findings of other studies (3, 24–31). Similar to Western societies, higher age (30, 31), longer disease duration (24), lower educational level (25, 30), manual jobs (3, 21), and worse physical function (26, 27) were associated with higher work disability. Interestingly, we did not find higher disease activity measured by DAS-28 to be associated with loss of work. Likely, variance in disease activity is captured in physical functioning as measured by the MHAQ. We find support of this hypothesis in the study by Drossaers-Bakker et al (32), who reported the DAS to show a variable course over 12 years of followup, but was the main determinant of the HAQ when entered in a multivariate analysis.

Similar to the findings of a recent Dutch study by Chorus et al (4), Lithuanian work disabled patients reported lower values on the physical domains of the SF-36, but also for emotional role and mental health. It is of note that the Lithuanian patients experienced worse quality of life for every domain compared with their Dutch counterparts.

Our study has some limitations. First, the relatively low response rate of 58% might have influenced the composition of the studied population. Patients my not participate for various reasons, from being too sick to being too busy with daily occupation because of relatively light disease. Second, the cross-sectional design does not allow adjusting for dynamic fluctuations of the disease and for societal processes. Third, the study is lacking information on reentering the labor force after leaving the job due to RA. Straaton et al (33) showed that up to 24% are able to return to permanent employment. Finally, the comparison of our data with the results of other studies is hampered because of the heterogeneity of the patients included, but also because most studies failed to adjust the figures on work status for age and sex.

Within the limits of the study, employment perspectives in patients with RA in Lithuania are unfavorable and even worse after the transition to a free-market economy. Comparable with studies in Western countries, worse physical function is strongly related to work disability, and work-disabled patients experience lower quality of life. Whether the more unfavorable situation of the Lithuanian patients is attributable to differences in access to and quality of health care, resulting in more important impairment of physical function, or to differences in social security systems or even to economic factors cannot be concluded from the study, but should not be neglected as possible explanatory factors.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES
  • 1
    Wolfe F, Lassere M, van der Heijde D, Stucki G, Suarez-Almazor M, Pincus T, et al. Preliminary core set of domains and reporting requirements for longitudinal observational studies in rheumatology. J Rheumatol 1999; 26: 4849.
  • 2
    Barrett EM, Scott DG, Wiles NJ, Symmons DP. The impact of rheumatoid arthritis on employment in the early years of disease: a UK community-based study. Rheumatology 2000; 39: 14039.
  • 3
    Young A. Socioeconomic deprivation and rheumatoid disease: what lessons the health service? Ann Rheum Dis 2000; 59: 7949.
  • 4
    Chorus AMJ, Miedema HS, Wevers CJ, van der Linden S. Labor force participation among patients with rheumatoid arthritis. Ann Rheum Dis 2000; 59: 54954.
  • 5
    Zink A, Braun J, Listing J, Wollenhaupt J. Disability and handicap in rheumatoid arthritis and ankylosing spondylitis: results from the German rheumatological database. J Rheumatol 2000; 27: 61322.
  • 6
    Pugner KM, Scott DI, Holmes JW, Hieke K. The costs of rheumatoid arthritis: an international long-term view. Semin Arthritis Rheum 2000; 29: 30520.
  • 7
    Urbanek T, Sitajova H, Hudakova G. Problems of rheumatoid arthritis and ankylosing spondilitis patients in their labor and life environments. Czechoslovak Med 1984; 7: 7889.
  • 8
    Dadoniene J, Uhlig T, Stropuviene S, Venalis A, Boonen A, Kvien TK. Disease activity and health status in rheumatoid arthritis: a case-control comparison between Norway and Lithuania. Ann Rheum Dis 2003; 62: 2314.
  • 9
    Arnett FC, Edworthy SM, Bloch DA, McShane DJ, Fries JF, Cooper NS, et al. The American Rheumatism association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum 1988; 31: 31524.
  • 10
    Fries JF, Spitz P, Kraines RG, Holman HR. Measurement of patient outcome in arthritis. Arthritis Rheum 1980; 23: 13745.
  • 11
    Ware JE, Gandek B. Methods for testing data quality, scaling assumptions, and reliability: the IQOLA Project approach: International Quality of Life Assessment. J Clin Epidemiol 1998; 51: 94552.
  • 12
    Guillemin F, Bombardier C, Beaton D. Cross-cultural adaptation of health-related quality of life measures: literature review and proposed guidelines. J Clin Epidemiol 1993; 46: 141732.
  • 13
    Prevoo ML, van't Hof MA, Kuper HH, van Leeuwen MA, van de Putte LB, van Riel PL. Modified disease activity scores that include twenty-eight-joint counts: development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis Rheum 1995; 38: 448.
  • 14
    Statistic of Lithuania 1999. Vilnius: Statistical Department of Lithuania; 2000.
  • 15
    Doeglas D, Suurmeijer T, Krol B, Sanderman R, van Leeuwen M, van Rijswijk M. Work disability in early rheumatoid arthritis. Ann Rheum Dis 1995; 54: 45560.
  • 16
    Kaarela K, Lehtinen K, Luukkainen R. Work capacity of patients with inflammatory joint diseases: an eight-year follow-up study. Scand J Rheumatol 1987; 16: 4036.
  • 17
    Reisine S, Fifield J, Winkelman DK. Employment patterns and their effect on health outcomes among women with rheumatoid arthritis followed for 7 years. J Rheumatol 1998; 25: 190816.
  • 18
    Young A, Dixey J, Cox N, Davies P, Devlin J, Emery P, et al. How does functional disability in early rheumatoid arthritis (RA) affect patients and their lives? Results of 5 years of follow-up in 732 patients from the early RA study (ERAS). Rheumatology 2000; 39: 60311.
  • 19
    Makisara GL, Makisara P. Prognosis of functional capacity and work capacity in rheumatoid arthritis. Clin Rheumatol 1982; 1: 11725.
  • 20
    van Jaarsveld CH, Jacobs JW, Schrijvers AJ, van Albada-Kuipers GA, Hofman DM, Bijlsma JW. Effects of rheumatoid arthritis on employment and social participation during the first years of disease in the Netherlands. Br J Rheumatol 1998; 37: 84853.
  • 21
    Sokka T, Kautiainen H, Mottonen T, Hannonen P. Work disability in rheumatoid arthritis 10 years after the diagnosis. J Rheumatol 1999; 26: 16815.
  • 22
    Albers LM, Kuper HH, van Riel PL, Prevoo ML, van 't Hof MA, van Gestel AM, et al. Socio-economic consequences of rheumatoid arthritis in the first years of the disease. Rheumatology 1999; 38: 42330.
  • 23
    Mau W, Bornmann M, Weber H. Work disability in the first year of chronic polyatrhritis. a comparison with members of the legal health insurance. Z Rheumatol 1997; 56: 17.
  • 24
    de Roos AJ, Callahan LF. Differences by sex in correlates of work status in rheumatoid arthritis patients. Arthritis Care Res 1999; 12: 38191.
  • 25
    Markenson JA. Worldwide trends in the socioeconomic impact and long-term prognosis of rheumatoid arthritis. Semin Arthritis Rheum 1991; 21(2 Suppl ): 412.
  • 26
    Callahan LF, Bloch DA, Pincus T. Identification of work disability in rheumatoid arthritis: physical, radiographic and laboratory variables do not add explanatory power to demographic and functional variables. J Clin Epidemiol 1992; 45: 12738.
  • 27
    Reisine S, Fifield J, Walsh SJ, Feinn R. Factors associated with continued employment among patients with rheumatoid arthritis: a survival model. J Rheumatol 2001; 28: 24008.
  • 28
    Allaire SH, Anderson JJ, Meenan RF. Reducing work disability associated with rheumatoid arthritis: identification of additional risk factors and persons likely to benefit from intervention. Arthritis Care Res 1996; 9: 34957.
  • 29
    Reisine S, McQuillan J, Fifield J. Predictors of work disability in rheumatoid arthritis patients: a five-year follow up. Arthritis Rheum 1995; 38: 16307.
  • 30
    Fex E, Larsson BM, Nived K, Eberhardt K. Effect of rheumatoid arthritis on work status and social and leisure time activities in patients followed 8 years from onset. J Rheumatol 1998; 25: 4450.
  • 31
    Wolfe F, Hawley DJ. The longterm outcomes of rheumatoid arthritis: work disability: a prospective 18 years study of 823 patients. J Rheumatol 1998; 25: 210817.
  • 32
    Drossaers-Bakker KW, de Buck M, van Zeben, Zwinderman AH, Breedveld FC, Hazes JMW. Long-term course and outcome of functional capacity in rheumatoid arthritis: the effect of disease activity and radiologic damage over time. Arthritis Rheum 1999; 42: 185460.
  • 33
    Straaton KV, Maisiak R, Wrigley JM, White MB, Johnson P, Fine PR. Barriers to return to work among persons unemployed due to arthritis and musculoskeletal disorders. Arthritis Rheum 1996; 39: 1019.