TEST-RETEST STUDY OF THE SIX-MINUTE WALK TEST IN PEOPLE WITH BIPOLAR DISORDER

Background: The multidisciplinary care for bipolar disorder is highly fragmented with limited opportunities for prevention and treatment of medical co-morbidities. We examined the reliability of the 6-minute walk test (6MWT). Secondary aims were to assess minimal detectable changes (MDC95), practice effects and the impact of clinical conditions. Subjects and methods: Two 6MWTs were administered within 3 days to 46 (23 male) inpatients with a DSM-V diagnosis of bipolar disorder. Physical complaints before and after the 6MWT were recorded. Patients completed the Quick Inventory of Depressive Symptomatology Self Report (QIDS-SR) and Hypomania Check List-32. Results: Patients walked 594.7 +/- 121.3 meters and 600.0 +/- 122.9 meters at the first and second test. The intraclass correlation coefficient was 0.98 (95% confidence interval 0.97-0.99). The MDC95 was 37.8 meters for men and 52.9 meters for women. No practice effect was detected. Longer illness duration, higher QIDS-SR scores and the presence of feet or ankle static problems or pain were independently related to shorter 6MWT distance accounting for 59.8% of the variance. Conclusion: The 6MWT is a clinically feasible tool for evaluating the functional exercise capacity in patients with bipolar disorder. Health care professionals should consider depression and physical pain when developing rehabilitation programmes.