This study builds upon our previous findings that ABLE reduced functional difficulties and conferred a one year survivorship benefit. In this study, we show that mortality rates were statistically significantly lower for the intervention group compared to the control group for up to two years, with mortality rates remaining lower for ABLE participants for up to 3.5 years from study entry. The risk of dying within 2 years from study entry was close to 8 times higher in control group participants than ABLE participants.
The mortality benefit to two years was similar in low and moderate mortality risk groups, although only attaining statistical significance in the moderate group (the largest of the three groups in our sample). This may be partially due to the small sample size in the low risk group. For this moderate risk group, risk of dying within 2 years from study entry was close to 11 times higher in control group participants than in ABLE participants. The pattern was slightly different in the high risk group, in which there was an early benefit for ABLE participants. However, that benefit did not last to the two year point. Although ABLE participants at each level of mortality risk (low, moderate, high) derived some intervention benefit, intervention participants at moderate risk sustained a statistically significant two year survival advantage compared to their control-group counterparts.
These findings suggest that a relatively brief, nonpharmacologic intervention that helps older people use cognitive, behavioral and environmental strategies to reach self-identified functional goals has survivorship benefits that persist. The survivorship advantage extended well beyond ABLE’s six-month active phase of hands-on intensive skills-training.
Reasons for prolonged survivorship are unclear. One explanation may be ABLE’s preventive home safety and referral functions. Previous research has shown that health professional visits reduced mortality.7,9,16
Nevertheless, medical referrals were not typical in ABLE. Another explanation may be social attention, although it seems unlikely that approximately 10 professional contact hours explains survivorship extending 3.5 years from study entry.
A more plausible explanation is that ABLE offered strategies that helped participants achieve personal functional goals. As reported previously, ABLE participants reported greater use of control-oriented strategies than control group participants at 6 and 12-month follow-ups.10
The Life Span Theory of Control suggests that as impairments encroach on performance abilities, individuals experience heightened vulnerability to environmental complexities and threats to personal control.17
Threats to or actual loss of control have significant negative health consequences; alternately, enhancing control contributes to well-being and survivorship.18,19,20
How does enhancing control support survivorship? Control-oriented strategies enable continued engagement in everyday activities, which may have some physiological as well as psychosocial benefits. Although pathophysiologic mechanisms are unclear,21
our findings are consistent with recent evidence on the dynamic interaction between frailty and living environments.22
There are other competing explanations than the benefits conferred by ABLE. Findings may be a result of attrition bias or selective mortality in the intervention group such that the highest risk patients die early, leaving a remaining pool of lower risk patients. Mortality rates are higher in the higher risk group, so the baseline risk distribution of those remaining alive slowly moves towards the lower risk groups. Since there is little mortality in the intervention group early on, however, we do not see this effect in the intervention group in the early period and so this does not explain the increase in the 6-month rates in the intervention group. Also, as a randomized study, any attrition effect should be the same in both groups in the absence of an intervention effect. It appears that the intervention delays mortality in a subset but eventually medical issues take over.
A potential limitation is that the database does not allow for multivariate risk adjustments or control of clinical variables (e.g., comorbidities, health service utilization, hospitalizations). Also, survival analyses were unplanned and post-hoc. Nevertheless, these are minor limitations given that the original study was a randomized trial with no large or statistically significant differences between treatment and control groups on study outcomes or health variables.
Another issue is representativeness. Similar to population-based studies of older adults with similar ages and functional problems, we found a 10% mortality rate at two years for our study sample overall.4
This suggests that our sample may be representative of the larger population of elders living at home with performance difficulties. ABLE participants had a mortality rate of 5.6%, below the rate for the control group (13.2%) and those in representative studies (10%). Although not our main focus, in our sample, individuals of low income and education were at the highest risk of mortality. This association is consistent with population-based health disparities research, again suggesting the representativeness of our sample.23,24
Several clinical implications can be derived. Interventions addressing disability are not typically part of medical management. Evidence shows that those most in need, frail, post-hospitalized, vulnerable elders, receive inadequate follow-up care.25,26,27
ABLE may be most beneficial for risk groups.
Yet, older adults with no functional difficulties also report using accommodations to perform activities. Use of accommodations by this independent group has been shown to reflect a subclinical stage predictive of frailty.28
Thus, older adults with incipient functional difficulties may also benefit from ABLE as suggested by the slight intervention advantage afforded to the low risk mortality group.
Essential to ABLE is its client-centered focus, use of problem-solving, active engagement of older adults in problem-identification and strategy-generating processes, and tailoring of strategies to fit needs, cultural preferences and environments. These elements resonate with an emerging vision for geriatric care,29,30
which emphasizes that patient-centered care and symptom management be integrated with medical management and become standard practice.
Overall, ABLE demonstrated that teaching elders new approaches to performing valued activities resulted in additional years of life. Further research is necessary to substantiate mortality findings using a pre-planned, hypothesis-driven randomized trial. Equally important is determining why ABLE lost its benefit, whether different dose, intensity or boosters prolong benefit, and how to integrate ABLE into other proven interventions (e.g., physical activity) to extend positive effects. Future research should clarify physiological mechanisms by which survivorship benefits are conferred, effects of ABLE on health utilization, and cost and cost-effectiveness of this promising program.