Six-minute walk test and health status assessment in sarcoidosis

The 6-min walk test has proved useful in assessing impairment and prognosis in various lung diseases.

A prospective study of 142 sarcoidosis patients seen during a 6-week period at one tertiary sarcoidosis clinic. All patients completed spirometry, 6-min walk testing, St. George Respiratory Questionnaire (SGRQ), fatigue assessment scale, and dyspnea score. Parameters assessed included the 6-min walk distance (6MWD) and the initial and lowest oxygen saturations during the test.

One hundred three of 142 patients had extrapulmonary manifestations, 10 patients had left ventricular dysfunction, and 14 patients had documented pulmonary hypertension. Seventy-three patients (51%) completed a 6MWD < 400 m, and 32 patients (22%) walked < 300 m. The 14 patients with documented pulmonary hypertension had a shorter 6MWD (median, 280 m; range, 61 to 404) than those without documented pulmonary arterial hypertension (median, 411 m; range, 46 to 747; p < 0.0001). Several components of the pulmonary function and quality of life correlated with 6MWD. Using a stepwise multiple regression analysis, only SGRQ activity component (t = - 7.498, p < 0.0001), FVC (t = 4.415, p < 0.0001), and lowest oxygen saturation (t = 2.55, p < 0.02) were independent predictors of 6MWD.

6MWD was reduced in the majority of sarcoidosis patients. Several factors were associated with a reduced 6MWD, including FVC, oxygen saturation with exercise, and self-reported respiratory health. Both 6MWD and quality of life measures are useful in assessing the functional status of sarcoidosis patients.