The Relationship Between Instrumental Activities of Daily Living and Hospitalizations: A Systematic Review and Meta-Analysis

Instrumental activities of daily living (IADL) have been defined as the activities for which their performance is necessary for continued independent living arrangements and that are more complex than routine activities of daily living. Evidence has reported the presence of IADL impairments in patients discharging from hospital. However, there is little research evaluating the role of IADLs as a modifiable risk factor in preventing hospitalizations among high-risk groups, such as heart failure. This oversight leaves gaps in discharge planning, in connecting patients to needed services that address impaired IADLs. The purpose of this dissertation was to improve knowledge of the relationship between IADLs and hospitalizations by: 1) describing the theory that underpins the relationship between IADLs and hospitalizations; 2) completing a systematic review to narratively synthesize the state of use of IADL scales across studies examining hospitalizations among high-risk groups (i.e., heart failure); 3) completing a meta-analysis to estimate the overall association between IADLs and hospitalizations among the high-risk groups; 4) conducting tests of moderation using meta-analytic techniques to determine whether the overall association between IADLs and hospitalizations varied based on certain IADL scale characteristics (e.g., number of components). Founded upon the Theory of Self-Care of Chronic Illness, the systematic search produced 4,932 articles, with 23 meeting criteria. The systematic review revealed that IADL discussions have been present in healthcare literature internationally since 1969; significant heterogeneity exists in the number of IADL components; the legacy work of Lawton and Brody (1969) remains prevalent but not panoptic; and IADLs have been studied in a wide variety of illnesses. The meta-analysis revealed that IADL impairments were positively associated with hospitalizations (OR=1.40, 95% CI: 1.24, 1.58; k=22, p<.001). Tests of moderation indicated that the IADL scale (QM=0.496, p=0.481) and item composition (QM=0.189, p=0.664) did not explain variation among effect sizes, indicating that the IADL scale formulation did not impact the relationship between IADLs deficits and hospitalizations. This dissertation provides compelling evidence that assessing IADLs may yield a significant opportunity to identify modifiable risk factors to reduce hospitalization. More work is needed to standardize IADL measurement at discharge to identify patients at high risk.