Impact of oral cyclophosphamide on health‐related quality of life in patients with active scleroderma lung disease: Results from the scleroderma lung study

Objective To assess the impact of cyclophosphamide (CYC) on the health‐related quality of life (HRQOL) of patients with scleroderma after 12 months of treatment. Methods One hundred fifty‐eight subjects participated in the Scleroderma Lung Study, with 79 each randomized to CYC and placebo arms. The study evaluated the results of 3 measures of health status: the Short Form 36 (SF‐36), the Health Assessment Questionnaire (HAQ) disability index (DI), and Mahler's dyspnea index, and the results of 1 preference‐based measure, the SF‐6D. The differences in the HRQOL between the 2 groups at 12 months were calculated using a linear mixed model. Responsiveness was evaluated using the effect size. The proportion of subjects in each treatment group whose scores improved at least as much as or more than the minimum clinically important difference (MCID) in HRQOL measures was assessed. Results After adjustment for baseline scores, differences in the HAQ DI, SF‐36 role physical, general health, vitality, role emotional, mental health scales, and SF‐36 mental component summary (MCS) score were statistically significant for CYC versus placebo ( P < 0.05). Effect sizes were negligible (<0.20) for all of the scales of the SF‐36, HAQ DI, and SF‐6D at 12 months. In contrast, a higher proportion of patients who received CYC achieved the MCID compared with placebo in the HAQ DI score (30.9% versus 14.8%), transitional dyspnea index score (46.4% versus 12.7%), SF‐36 MCS score (33.3% versus 18.5%), and SF‐6D score (21.3% versus 3.8%). Conclusion One year of treatment with CYC leads to an improvement in HRQOL in patients with scleroderma lung disease.