Physical activity in older persons with eye diseases. Applicability of wrist-worn accelerometer

Background and objectives. Physical activity (PA) impacts age-related diseases but its measurement is difficult. The acceptance of wrist-worn accelerometers (ACC) in older patients with eye diseases was evaluated and the results were compared with a validated activity questionnaire. Materials and methods. In this study 50 patients underwent a clinical examination and were interviewed with the International Physical Activity Questionnaire (IPAQ). They then wore an ACC for 7 days and then for 30 days. After descriptive analysis of the data, influencing factors on the PA were assessed using multiple, linear models. Results. A total of 94% of participants wore the ACC for 7 days and 74% for 30 days. For 36 patients complete data were available. In comparison, IPAQ (e.g. moderate PA: 1183.4 +/- 864.3 min/week) vs. ACC across 7 and 30 days (248.5 +/- 266.0 min/week and 248.8 +/- 190.6 min/week, respectively) showed substantially higher results (p < 0.05 for both intervals). The ACC data across 7 and 30 days were comparable (e.g. high PA: 25.4 +/- 33.7 min/week and 22.5 +/- 29.0 min/week). In multiple, linear models body mass index (BMI) was associated with 7 days moderate activity (beta = -0.22 [95% confidence intervals CI: -21.7; -1.9]; p = 0.021) and vigorous activity (beta = -0.35 [95% CI: -4.3; -0.5]; p = 0.033) as well as 30 days vigorous activity (beta = -0.45 [95% CI: -5.9; -0.1]; p = 0.044). Other factors such as better visual acuity, age and gender were not associated. Conclusion. The use of ACCs are acceptable to the majority of older patients with eye diseases. The results of ACC are more precise with lower variation, and much lower PA than those of a comparable activity questionnaire. Measurement over 7 days is sufficient for capturing the average PA in older patients and can be easily applied in clinical trials.