Nonspecific symptoms explain functional limitations in older adults better than disease-specific symptoms

Older adults often have multiple diseases and age-related physiologic changes that may present with nonspecific symptoms such as fatigue or dizziness. Identifying symptoms that are most strongly associated with functioning may guide symptom management. This study examined the association of nonspecific and disease-specific symptoms with functional limitations in community-dwelling older adults over a 23-year period.

Data were from the Precipitating Events Project, a longitudinal cohort study, involving 754 adults aged 70 and older [mean (standard deviation) age of 78.9 (5.3) years, 64.6% female] from South Central Connecticut, USA. During monthly telephone interviews, 20 symptoms and limitations in 13 daily activities were assessed. Associations were cross-sectionally and longitudinally tested using trends in proportions (Z-scores) and generalized estimating equations models.

The three strongest trends in proportions with functional limitations were for the nonspecific symptoms: 'memory problems' (Z-score 60.9), 'arm or leg weakness' (58.5), and 'fatigue' (54.7). The lowest z-scores were for the disease-specific symptoms 'cold or flu symptoms' (12.3), 'decreased eyesight' (17.8), and 'chest pain' (19.9). The three nonspecific symptoms: 'fall' [regression coefficient b = 1.40, confidence interval (CI) 1.28-1.52], 'arm or leg weakness' (b = 1.13, CI 1.02-1.23), and 'dizziness' (b = 1.12, CI 1.04-1.20) had the strongest cross-sectional associations with functional limitations. In longitudinal models with a 1-month time lag, these associations attenuated.

Nonspecific symptoms had stronger associations with functional limitations than disease-specific symptoms, underscoring the importance of addressing nonspecific symptoms in older adults. The presence of cross-sectional, but not longitudinal, associations likely reflects an immediate rather than sustained impact on functioning.