Background: Although most epidemiologic studies have defined disability in basic activities of daily living (BADLs) as dependence, some investigators have argued that BADL disability should be defined as degree of difficulty.
Objective: To determine whether the responses to questions about difficulty and dependence provide complementary information that together can depict the continuum of disability more fully than the response to either question alone.
Setting: General community.
Participants: 1065 persons 72 years of age and older.
Measurements: On the basis of self-reported information collected at baseline, participants were categorized into three BADL groups: independent without difficulty, independent with difficulty, and dependent. Additional baseline information was collected on several measures of higher-level function and physical performance. Follow-up information was collected on regular home care visits and BADL function at 1 and 3 years and on hospitalizations, admissions to skilled-nursing facilities, and deaths over a 4-year period.
Results: In a cross-sectional analysis, the proportion of participants with poor higher-level function and physical performance increased substantially across the three BADL groups. In a longitudinal analysis, the rates of hospitalization and regular home care visits for the independent without difficulty group, the independent with difficulty group, and the dependent group were 46%, 57%, and 72% (P < 0.001) and 17%, 30%, and 49% (P < 0.001), respectively; survival curves for admission to a skilled-nursing facility and death differed significantly for each pair-wise comparison. Among persons who were BADL independent, those with difficulty were significantly more likely to develop BADL dependence over a 3-year period than those without difficulty (31% compared with 18%; P < 0.001).
Conclusions: In the assessment of BADL function in older persons, questions about difficulty and dependence provide complementary information that together can depict the continuum of disability more fully than either question alone.