Significance of fatigue in patients with rheumatoid arthritis

Background

Fatigue is a frequent and debilitating problem in people with rheumatoid arthritis (RA). However, there are few prospective studies evaluating the economic impact of fatigue in people with RA.

Objectives

To study the economic correlates of fatigue in patients with RA, and to evaluate the impact of fatigue on costs of medical care and missed days of work.

Patients and methods

A total of 6551 consecutively diagnosed RA patients with 35,371 person years of follow-up are currently enrolled in the ARAMIS postmarketing surveillance program. Patients complete semi-annual Stanford Health Assessment Questionnaires on their disease symptoms, severity, medication use (including over-the-counter medications), adverse events and healthcare resource utilization including hospitalizations and emergency room visits. Patients also report on measures of indirect costs such as missed days of work and days when they were unable to do nonemployment-related activities. All self-reported hospitalizations are audited, and discharge summaries are reviewed by a physician. Complete ascertainment of all deaths is obtained from regular searches of the US National Death Index database. Since 1987, all patients were asked to report on the presence of tiredness or fatigue in their semi-annual assessment. Medical costs of care are estimated based on 2002 Medicare reimbursement rates and on 2002 average wholesale medication costs. Statistical comparisons were made between periods when patients reported fatigue and those when no fatigue was reported.

Results

A total of 2699 patients (mean age, 58.3 years; 78% female) with 12,458 person-years of follow-up answered the fatigue question. The point prevalence of fatigue varied from 57.5% in 1987 to 67.2% in 2000 (average, 56.9%). For comparison, the point prevalence of fatigue in 1916 patients with osteoarthritis (mean age, 66 years; 76% female) was 49.6% (P < 0.001, after adjustment for confounding demographic variables). Patients with fatigue reported significantly higher annual direct medical costs of care compared with those who were not fatigued ($4621.70 ± 241.66 vs $2131.42 ± 265.68 respectively, P < 0.001). During the 6-month periods when they reported fatigue, patients missed an average of 1.93 days (standard error of the mean [SEM], 0.11) of work, and were unable to do nonemployment-related activities for 12.31 days (SEM, 0.34). In the 6-month time periods when no fatigue was reported, patients only missed an average of 0.98 days (SEM, 0.10) of work and were unable to do nonemployment-related activities for 5.44 days (SEM, 0.34) (P < 0.001 for both comparisons). Mutivariate analysis showed that the costs of medical care were strongly correlated with the presence of fatigue (P < 0.02), after adjusting for age, gender, duration of RA and education level.

Conclusions

Fatigue is a common symptom in patients with RA. Patients with fatigue have significantly higher costs of medical care and miss more days of work compared with those who do not have fatigue. It is important to measure fatigue in clinical trials of innovative therapies since this is an important reason for poor quality of life, and is strongly correlated with disease severity and direct and indirect medical costs.