Effect of Inpatient and Outpatient Pneumonia on Mobility Disability, Gait Speed, and Physical Activity in Older Adults.

Pathophysiological changes caused by pneumonia may influence physical functioning in older adults. This study was a secondary analysis of the Lifestyle Interventions and Independence for Elders (LIFE) Study. The LIFE Study included 1635 individuals over an average follow-up of 2.6 years at eight clinical sites during 2010-2013. Adults ≥70 years-old with mobility limitations (Short Physical Performance Battery score ≤9) were randomized to a physical activity (exercise) intervention or health education control arm. This analysis evaluated the association between pneumonia events and major mobility disability (MMD), gait speed, and physical activity levels. Pneumonia events, classified as inpatient or outpatient, were assessed by self-report during longitudinal follow-up. MMD was measured by the inability to complete a 400-m walk test, or other proxies, as a binary outcome and separately analyzed as "short-term" and "long-term" MMD. Short-term MMD was defined as MMD occurring in the assessment period immediately following (between 1-day to 6-months after) a pneumonia event and long-term was in the following assessment period (6 to 12 months after the event). Short- and long-term gait speed was similarly recorded during the walk test in meters per second (m/s) and measured on a linear scale. Physical activity levels were captured via accelerometry and shown visually. Mixed-effects repeated measures regression adjusted for intervention assignment, baseline demographics, comorbid conditions, and frailty. Among the 1635 participants, = 174 (10.7%) had a pneumonia event of which 80 (46% of events) were hospitalized. Those with pneumonia during follow-up had higher baseline medication use, prior hospitalizations, and higher prevalence of lung disorders but similar baseline functioning. Pneumonia hospitalization was associated with a 4-fold increase [OR = 4.1 (3.2-5.0)] and outpatient events were associated with a 2-fold increase [OR = 2.6 (2.1-3.1)] in the odds of short-term MMD. Pneumonia hospitalizations, but not outpatient events, were associated with a nearly 10% decrement in short-term gait speed. Pneumonia events were not associated with either long-term MMD or gait speed outcomes. Physical activity levels decreased from baseline immediately following the pneumonia episode (10-30% reductions) and returned to baseline after 6 months. These results emphasize the importance of managing pneumonia risk factors to prevent disease in order to maintain physical independence and activity in older adults.