Impact of Psychological Deficits and Pain on Physical Activity of Patients with Interstitial Lung Disease

Purpose The impact of psychological deficits and pain on physical activity has not been adequately studied in patients with fibrotic interstitial lung disease (ILD). We aimed to determine the association of depression, anxiety, sleep quality, and pain with physical activity in fibrotic ILD. Methods Waist ActiGraph activity monitors were worn for seven consecutive days to track step counts and moderate-to-vigorous physical activity (MVPA) minutes at baseline and 6-month follow-up. Psychological deficits and pain were assessed using the Hospital Anxiety and Depression Scale, the Pittsburgh Sleep Quality Index, and the Brief Pain Inventory. Multivariable linear regression was used to determine if each deficit independently predicted physical activity when adjusted for potential confounders. Results A total of 111 patients were recruited, with 91 of these patients completing the 6-month follow-up. Median step count and MVPA minutes were 3853 steps/day (interquartile range 2236-6805) and 87 (17-225) min/week at baseline, respectively, with no significant changes at follow-up. Borderline or abnormal depression and anxiety scores were present in 19% and 22% of patients, respectively. Poor sleep quality and moderate-to-severe pain were present in 61% and 9% of patients. Higher depression scores were associated with fewer baseline and follow-up step counts and lower MVPA minutes at follow-up on unadjusted analysis; higher pain severity scores were associated with fewer baseline step count. Pain severity remained an independent predictor of reduced step count after adjusting for patient's age, smoking status, ILD severity, and weather variables. Conclusions Pain severity may be a potentially modifiable determinant of physical activity in patients with fibrotic ILD.