Recovery from Severe Disability that Develops Progressively Versus Catastrophically: Incidence, Risk Factors, and Intervening Events

Background Few prior studies have evaluated recovery after the onset of severe disability or have distinguished between the two subtypes of severe disability. Objectives To identify the risk factors and intervening illnesses and injuries (i.e., events) that are associated with reduced recovery after episodes of progressive and catastrophic severe disability. Design Prospective longitudinal study of 754 nondisabled community-living persons, aged 70 years or older. Setting Greater New Haven, CT, March 1998 to December 2016. Participants A total of 431 episodes of severe disability were evaluated from 385 participants: 116 progressive (115 participants) and 315 catastrophic (270 participants). Measurements Candidate risk factors were assessed every 18 months. Functional status and exposure to intervening events leading to hospitalization, emergency department visit, or restricted activity were assessed each month. Severe disability was defined as the need for personal assistance with three or more of four essential activities of daily living. Recovery was defined as return to independent function (no disability) within 6 months of developing severe disability. Results Recovery occurred among 35.3% (95% confidence interval [CI] = 26.0%-48.0%) and 61.6% (95% CI = 53.5%-70.9%) of the 116 progressive and 315 catastrophic severe disability episodes, respectively. In the multivariable analyses, lives alone, frailty, and intervening hospitalization were each independently associated with reduced recovery from progressive disability, with adjusted hazard ratios (95% CIs) of 0.31 (0.15-0.64), 0.23 (0.12-0.45), and 0.27 (0.08-0.95), respectively, whereas low functional self-efficacy, intervening restricted activity, and intervening hospitalization were each independently associated with reduced recovery from catastrophic disability, with adjusted hazard ratios (95% CIs) of 0.56 (0.40-0.81), 0.55 (0.35-0.85), and 0.45 (0.31-0.66), respectively. Conclusions Recovery of independent function is considerably more likely after the onset of catastrophic than progressive severe disability, the risk factors for reduced recovery differ between progressive and catastrophic severe disability, and subsequent exposure to intervening illnesses and injuries considerably diminishes the likelihood of recovery from both subtypes of severe disability.