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. Author manuscript; available in PMC: 2020 Jul 1.
Published in final edited form as: JACC Heart Fail. 2019 May 8;7(7):537–546. doi: 10.1016/j.jchf.2018.12.008

Financial Incentives to Increase Cardiac Rehabilitation Participation among Low-Socioeconomic Status Patients: A Randomized Clinical Trial

Diann E Gaalema a,b, Rebecca J Elliott a, Patrick D Savage c, Jason L Rengo c, Alex Y Cutler a, Irene Pericot-Valverde a, Jeffrey S Priest d, Donald S Shepard e, Stephen T Higgins a,b, Philip A Ades c
PMCID: PMC6599560  NIHMSID: NIHMS1516979  PMID: 31078475

Abstract

Objective:

To examine the efficacy of patient financial incentives to increase CR participation and completion among Medicaid patients.

Background:

Participation in cardiac rehabilitation (CR) reduces morbidity, mortality, and hospitalizations while improving quality of life. Lower-socioeconomic status (SES) patients are much less likely to attend and complete CR despite being at increased risk for recurrent cardiovascular events.

Methods:

130 Medicaid-enrolled individuals with a CR qualifying cardiac event were randomized 1:1 to receive financial incentives on an escalating schedule ($4-$50) for completing CR sessions or to usual-care. Primary outcomes were CR participation (number sessions completed) and completion (≥30 sessions completed). Secondary outcomes included changes in socio-cognitive measures (depressive/anxious symptomology, executive function [ExecF]), body composition (waist circumference, body mass index), and fitness (peak VO2) over 4 months, and the combined number of hospitalizations and Emergency-Department (ED) contacts over one year.

Results:

Patients randomized to the incentive condition completed more sessions (22.4 vs. 14.7, p=0.013) and were almost twice as likely to complete CR (55.4% vs. 29.2%, p=0.002) as controls. Incentivized patients were also more likely to experience improvements in ExecF (p< 0.001), although there were no significant effects on other secondary outcomes. Patients who completed ≥30 sessions had 47% fewer combined hospitalizations and ED visits (p=0.014), which was mirrored by a non-significant trend by study condition with 39% fewer hospital contacts in the incentive condition (p=0.079).

Conclusions:

Financial incentives improve CR participation among, lower-SES patients following a cardiac event. Increasing participation among lower-SES patients in CR is critical to positive longer-term health outcomes.

Keywords: executive function, hospitalization, risk-factor control, fitness

Condensed Abstract

Outcomes are reported for a randomized clinical trial testing the efficacy of patient-level financial incentives to improve cardiac rehabilitation participation among lower-socioeconomic status patients. Patients randomized to the incentive condition completed significantly more sessions (22.4 vs. 14.7) and were almost twice as likely to complete the program (55.4% vs. 29.2%) than controls. Incentivized patients also reported significant improvement in executive function, although improvements in other secondary outcomes did not differ by condition. Patients who completed the program had fewer hospitalizations and ED visits than those who did not.

Cardiac rehabilitation (CR) is a structured program of supervised exercise and risk-factor control that is standard of care following a major cardiac event such as myocardial infarction (MI) or coronary revascularization(1). Attendance at CR following a major cardiac event is associated with a 26% reduction in cardiovascular mortality, a 31% reduction in one-year hospital readmissions(2,3), and a 21%−34% reduction in 5-year all-cause mortality(4). CR is also beneficial for individuals with chronic systolic heart failure (CHF)(5,6), although participation rates for these patients is extremely low(7).

Lower-socioeconomic status (SES) patients shoulder a higher proportion of the morbidity and mortality resulting from cardiovascular disease(8). Lower-SES patients have high-risk cardiac profiles including low fitness and high rates of smoking, obesity, and diabetes mellitus(9) that result in increased rates of cardiac events(9,10). Lower-SES patients also have higher rates of CHF(11) and worse post-hospitalization outcomes, with 1-year mortality rate double that of more affluent patients(9,10,12). These SES disparities are largely accounted for by modifiable behaviors, (e.g. smoking, physical inactivity(9,10,12,13)). Thus, increased risk following a cardiac event in lower-SES individuals is likely modifiable by attending secondary-prevention interventions such as CR.

Despite proven benefits of CR, overall attendance rates for eligible patients has been low, ranging from 14–34%(14–16). Attendance among lower-SES patients is even poorer. Within Medicare patients (≥65 years), those who are also enrolled in Medicaid (i.e., lower-SES) attend CR at 20–45% of the rate of higher-SES patients(4,15,16). The pattern is similar in studies using education as an SES marker, where those with limited educational attainment were a third less likely to attend CR(14,17). Part of this lower attendance could be attributable to disparities in initial CR referral(18).

Patients must also be retained in CR. Overall, completion rates for patients who have started CR are estimated at about 75%(19,20), but disparities exist. Lower-SES patients complete fewer sessions than higher-SES counterparts(21). Given that completing more CR sessions is associated with greater health benefits(4,22), the crucial outcome should not just be to increase enrollment, but to maximize number of sessions completed. In the latest systematic review of interventions to improve adherence, only one study aimed to increase number of CR sessions completed, and the intervention was unsuccessful(23). Additionally, to our knowledge, not a single study, other than our own study reporting pilot data from the current trial(24), has focused on increasing CR participation in lower-SES patients.

Incentive-based interventions can be a highly efficacious approach to altering health behaviors among disadvantaged populations. One approach, contingency management, involves providing financial incentives contingent on objective evidence of behavior change. The use of financial incentives first garnered attention as a method that increased treatment participation and abstinence from drug use among cocaine-dependent outpatients(25). The incentives-based model was subsequently shown to be effective at increasing treatment participation and abstinence from a wide variety of substances(26). Additionally, the use of financial incentives has been successful in promoting adherence to health-care visits in predominantly lower-SES populations(27,28). In CR, where health effects appear dose-dependent(4,22), the ability to sustain participation would be of considerable clinical benefit.

Lower-SES patients have higher-risk cardiac profiles and worse outcomes following an acute cardiac event. Efficacious interventions for getting these patients into proven treatment are needed. Financial incentives are efficacious for modifying other health behaviors in lower-SES populations, especially for promoting attendance at healthcare visits. Thus, this randomized clinical trial was designed to test the efficacy of financial incentives for increasing CR participation among recently hospitalized Medicaid-insured cardiac patients.

Methods

Study Design

This study was a 2-arm randomized clinical trial (Clinicaltrials.gov registration number: NCT02172820). All participants were expected to complete assessments at baseline and 4-months following baseline assessment and were offered compensation and travel reimbursement for assessments. Participants randomized to the incentive intervention received financial incentives for completion of CR sessions. Patients randomized to the control condition did not earn incentives. The CR program has been described in detail elsewhere(1,29), but consists of up to 36 outpatient exercise sessions, generally 2–3 weekly. The program is progressive and adaptive with an eventual goal of exercise duration of 45 minutes at 70–85% of baseline peak exercise heart rate. The program also includes educational sessions on stress management, healthy nutrition, medication use, symptom recognition, heart-failure teaching, benefits of exercise, and risk-factor control. For this CR program Medicaid was billed for CR sessions attended, there were no co-pays (Vermont policy), and while patients were responsible for transportation costs, parking was free.

Participation was defined as attending scheduled sessions and completing recommended exercise and other scheduled activities. Program staff verified participation. Incentives were distributed as cash immediately upon session completion. Participation in an introductory group meeting and in the initial exercise session earned participants $20 each. Participation in subsequent exercise sessions were incentivized using an escalating payment schedule. Participation in the second exercise session earned $4 with each subsequent session completed increasing incentive value by $2 up to a maximum of $50 per session (total possible incentive earnings $1238). Failure to attend a session (unless advanced notice was given) resulted in no earnings for that session and the amount possible to be earned in the next scheduled session was reset to $4. Successfully participating in two consecutive sessions following a reset, returned incentive value to the amount it was prior to the reset. This escalating incentive schedule combined with a reset contingency has been experimentally demonstrated to promote periods of continuous adherence(30).

Study Population

Recruitment occurred from April 2014 to January 2017 (Figure 1). Study participants included 130 Medicaid-enrolled patients hospitalized for CR qualifying events (acute MI, coronary artery bypass grafting surgery, heart valve replacement/repair, percutaneous coronary intervention [with or without stent placement], stable outpatient chronic systolic heart failure). Eligibility criteria included being enrolled in Medicaid or other state-supported insurance and residing in the catchment area for the University of Vermont Medical Center Cardiac Rehabilitation Program without plans to leave the area. Patients were ineligible if they had participated in CR in the past 5 years (defined as completion of ≥5 sessions), were non-English speaking, had dementia or current untreated Axis 1 psychiatric disorder other than nicotine dependence, had longevity-limiting systemic disease that would preclude participation (e.g. advanced cancer), or had comorbidities that would preclude participation in supervised exercise (e.g. angina at rest, uncontrolled ventricular arrhythmias, severe arthritis or lung disease, NYHA class 4 chronic heart failure).

Figure 1: Study Consort diagram.

Figure 1:

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CHART CONSORT Flow Diagram

Recruitment and Randomization

Potentially eligible patients were approached by research staff following their qualifying event. Upon confirming eligibility and receipt of written consent, participants were allocated using sealed envelopes, based on 1:1 randomization to intervention or control conditions. Following consent all participants were referred to CR. Staff collecting outcome data were blind to condition assignment. The study was approved by the University of Vermont Institutional Review Board.

Study participants were not separated from other patients during CR sessions. However, they comprised a minority of the CR population at any one time and did not tend to interact with each other. Research staff interacted with all CR participants during sessions regardless of study participation/condition. To reduce potential negative bias the benefits of being in the study generally (e.g. assessment earnings, thorough health checks during assessments) were emphasized. Participants did not report negative feelings towards other participants, although some did report mild disappointment in being assigned to the control group.

Study Outcomes

The primary study outcomes were the number of CR sessions completed and completion of CR as defined by completing ≥ 30 exercise sessions. Secondary outcomes included changes between baseline and 4-month assessment in fitness (Peak VO2 directly measured by expired gas analysis or estimated by metabolic equivalents), body composition (body mass index [BMI], waist circumference), socio-cognitive measures (Achenbach System of Empirically Based Assessment(31), Behavior Rating Inventory of Executive Function(32), Stop Signal Task(33)), and quality of life (MacNew Cardiac Health Status Questionnaire(34)). Basic clinical and demographic characteristics (age, sex, educational attainment, race/ethnicity, smoking status, BMI, CR-qualifying diagnosis) were collected at time of consent. Hospital contacts (ED visits and inpatient hospitalizations) were obtained for each patient for one year beginning one-month after hospital discharge. Contacts were extracted from the electronic health record by Medical Center staff otherwise unaffiliated with the study.

Statistical Analysis

Characteristics of individuals randomized to the two conditions were compared with Chi-square goodness-of-fit test or Fisher’s Exact Test for categorical variables and Student’s t-test or Wilcoxon Rank Sum Test for continuous variables. Number of sessions completed was analyzed both as a continuous variable using the Wilcoxon Rank Sum Test or converted into a binary categorical variable (<30 sessions vs. ≥30 sessions) and examined using Chi-square. Logistic regression was used to examine predictors of CR completion. Univariate logistic regression was conducted with seven possible predictors (treatment condition, sex, qualifying diagnosis, smoking status prior to hospitalization, age at consent, educational attainment, and BMI); variables that contributed to the outcome at p ≥ 0.25 were included in an initial model. This was winnowed to predictors achieving a significance level of p < 0.05. All variables either initially excluded or dropped were tested again, one-by-one, in a model with only significant predictors. Interactions between significant predictors that remained in a tentative final model were tested.

Changes over time were assessed using paired differences in scores from intake to four months for: BMI, waist, fitness (peak VO2), MacNew, self-reported executive function (GEC), SSRT (stop signal reaction time), and ASEABA (anxiety/depression). Analyses were conducted with the entire sample by treatment condition and by completion status (i.e., <30 sessions vs. ≥30 sessions). Due to non-normal distributions Wilcoxon Signed Rank Test was used. Contributions of other variables (treatment condition, sex, surgical status, current smoker, BMI, age) to changes in secondary outcomes were examined using analyses of covariance (ANCOVA).

Hospital contacts, (hospitalizations and ED visits combined), given the proportion of participants with zero contacts (39.2%), were analyzed using simple negative binomial regression models. Two models were used to predict number of hospital contacts, one with treatment condition and one with completer status (<30 vs. ≥30) as the sole predictor.

Using propensity-based matching results(16) expected discounted life years gained (EDLYG) per CR participant was derived based on sessions completed (n) as EDLYG = a(1-exp(−b-cn)), where a=9.9873 years (additional years per additional 5-year survivor), b=0.0459 (the 5-year mortality reduction from initiating CR), and c=0.0023 (the 5-year mortality reduction from each CR session). The cost of each CR session to the health system included incentives earnings (where applicable) plus 30% for incentives administration based on a comparably complex trial(35) as well as the Medicare allowed payment ($102). The preliminary incremental cost-effectiveness ratio (ICER) equals EDLYG divided by the program’s incremental cost. CIs were derived from 1,000 bootstrap replications.

The study was designed to have >80% power to detect a difference in CR attendance participation rates of 20%. Across all tests, statistical significance was defined as p < 0.05 (2-tailed) and 95% CIs.

Results

Participant Characteristics

Demographic and clinical characteristics were collected at consent on all 130 participants and did not differ between treatment conditions (Table 1). Measures gathered at the intake assessment differed only on stop signal reaction time (a component of ExecF), which was higher (more impulsive) in the incentive condition (p = 0.010). Participants were representative of a high-risk population. Education levels varied widely, and patients had considerable psychiatric and other medical comorbidities. Elevated depressive or anxious symptomology was present in 59% of participants, 40% had elevated problem scores on self-reported ExecF, average BMI was in the obese range, and 42% were current smokers. Eight of 130 patients (6%) carried a primary diagnosis of systolic heart failure. Left ventricular ejection fraction was ≤45% for 24/130 patients and for this group, mean ejection fraction was 34.5% ± 10.2% (range 17–45%). Of these 24 patients, 23 were on evidence-based medical therapy of beta blocker and angiotensin inhibitor or receptor blocker.

Table 1.

Participant Characteristics

n All
(n = 130)		 Incentives
(n = 65)		 No Incentives
(n = 65)		 p
Age (M ± SD) 130 57.1 ± 10.2 58.5 ± 11.0 55.8 ± 9.2 0.137
Female 130 49 (38%) 28 (43%) 21 (32%) 0.278
Race 130
  White 122 (94%) 61 (94%) 61 (94%) 1.000
  Non-white 8 (6%) 4 (6%) 4 (6%)
No. years education (M ± SD) 121 12.7 ± 2.7 12.4 ± 2.5 12.9 ± 2.9 0.347
Smoking before hospitalization 130 55 (42%) 27 (42%) 28 (43%) 1.000
CR Qualifying Diagnosis 130
  MI 63 (48%) 32 (49%) 31 (48%) 1.000
  PCI 78 (60%) 44 (68%) 34 (52%) 0.107
  CABG 16 (12%) 5 (8%) 11 (17%) 0.181
  Valve repair/replacement 16 (12%) 6 (9%) 10 (15%) 0.424
  Systolic CHF 8 (6%) 3 (5%) 5 (8%) 0.718
  Stable angina 2 (2%) 1 (2%) 1 (2%) 1.000
  CAD (in absence of the above) 6 (5%) 2 (3%) 4 (6%) 0.680
Fitness in PVO2 (M ± SD) 112 17.3 ± 5.5 17.37 ± 6.2 13.22 ± 4.6 0.883
Left Ventricular Ejection Fraction (%) 130 53.1±13.0 53.4±2.4 52.8±13.8 0.813
BMI (M ± SD) 130 32.1 ± 7.6 32.2 ± 8.2 32.0 ± 7.0 0.872
Waist (in.) (M ± SD) 105 42.6 ± 7.1 42.1 ± 7.6 43.0 ± 6.5 0.488
MacNew (M ± SD) 112 5.1 ± 1.1 5.3 ± 1.1 5.0 ± 1.1 0.147
FS Est IQ (M ± SD) 103 100.0 ± 17.8 100.4 ± 17.9 99.7 ± 17.9 0.844
ASEBA Anxiety/Depression (M ± SD) 97 59.8 ± 9.3 60.2 ± 9.9 59.4 ± 8.8 0.673
BRIEF-A (M ± SD) 105
  GEC 55.9 ± 11.8 56.4 ± 11.5 55.5 ± 12.1 0.694
D-KEFS (M ± SD)
  Trail Making 104 9.7 ± 3.2 9.7 ± 3.1 9.7 ± 3.2 0.934
  Tower 84 10.1 ± 3.0 9.7 ± 3.0 10.7 ± 3.0 0.127
SST (Seconds, M ± SD)
  GoRT 98 664.0 ± 121.1 667.6 ±123.4 660.4 ± 119.8 0.770
  SD GoRT 98 174.4 ± 60.5 178.0 ± 63.0 170.8 ± 58.2 0.563
  SSRT 98 207.8 ± 77.0 227.6 ± 91.3 188.0 ± 53.4 0.010
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Note. M = Mean. SD = Standard deviation. Categorical variables were tested using Fisher’s Exact Test. Continuous variables were tested using the Student’s t-test. Participants could have more than one qualifying diagnosis so percentages add to more than 100%. ASEBA and BRIEF scores are reported as T-scores. MI = myocardial infarction. PCI = percutaneous intervention. CABG = coronary artery bypass graft. CHF = chronic heart failure. CAD = coronary artery disease. BMI = body mass index. FS Est IQ = Full Scale Estimated Intelligence Quotient. ASEBA = Achenbach System of Empirically Based Assessment. BRIEF-A = Behavioral Rating Inventory of Executive Function - Adult. GEC = Global Executive Composite. D-KEFS = Delis-Kaplan Executive Function System. SST = Stop Signal Task. GoRT = Go Reaction Time. SD GoRT = Standard Deviation of Go Reaction Time. SSRT = Stop Signal Reaction Time.

Primary outcomes (i.e., number of CR sessions completed and proportion completing ≥30 sessions) and hospital utilization (hospitalizations and ED visits) were collected for all 130 participants. The trial ended after one-year hospital data collection was completed. Of the 130 randomized, 112 (86%) attended the initial assessment (55 in the incentive condition, 57 in the control). Of those who completed an intake assessment, 103 (92%) completed the 4-month follow-up assessment. Assessment attendance did not differ by condition.

CR Participation and Completion

Participants in the incentive condition completed more CR sessions (22.4 vs. 14.7, p = 0.013) and were almost twice as likely (55.4% vs. 29.2%, p = 0.002) to complete CR than those in the control condition (Figure 2). Percent who attended at least one session did not differ by condition. Only two variables predicted CR completion: being assigned to the incentive condition (OR 3.38, CI: 1.55–7.38) and not being a current smoker at the time of hospitalization (OR 4.55, CI: 2.02–10.25). There was no significant interaction between these two variables.

Figure 2: Cardiac Rehabilitation Participation (Central Illustration):

Figure 2:

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Survival plot of participation by study condition across CR sessions.

Fitness, Quality of Life, and Body Composition

Measures of fitness (peak VO2) and cardiac-specific quality of life (MacNew) improved in all patients between intake and follow-up (Ps < 0.001) but did not differ by treatment condition or completion status (Table 2). The only significant predictor of change in peak VO2 was smoking status, with current smokers improving less (p = 0.028). Measures of body composition (waist circumference and BMI) did not change significantly although there was a trend towards greater decrease in waist circumference among those in the incentive compared to the control condition (p = 0.054) and in program completers compared to dropouts (p = 0.077) (Table 2). No other variable examined significantly predicted changes in BMI or waist circumference.

Table 2.

Secondary Outcomes: Change from Baseline to 4-Month Assessment

Intake 4 Months %
Change		 p
n M M
Peak VO2
  All 112 17.29 18.93 9.49 <0.001
  No Incentives 57 17.22 19.38 12.54 <0.001
  Incentives 55 17.37 18.47 6.33 0.001
  Completed <30 Sessions 57 17.31 18.77 8.43 0.004
  Completed ≥30 Sessions 55 17.28 19.04 10.19 <0.001
MacNew
  All 111 5.10 5.55 8.82 <0.001
  No Incentives 57 4.94 5.47 10.73 <0.001
  Incentives 54 5.28 5.63 6.63 0.001
  Completed <30 Sessions 57 5.09 5.41 6.29 0.040
  Completed ≥30 Sessions 54 5.12 5.65 10.35 <0.001
Waist
  All 105 42.56 42.28 −0.66 0.090
  No Incentives 53 43.03 42.93 −0.23 0.635
  Incentives 52 42.07 41.60 −1.12 0.055
  Completed <30 Sessions 53 43.42 43.87 1.04 0.680
  Completed ≥30 Sessions 52 41.68 41.10 −1.39 0.077
BMI
  All 130 32.13 32.52 1.21 0.856
  No Incentives 65 32.02 32.62 1.87 0.722
  Incentives 65 32.23 32.40 0.53 0.633
  Completed <30 Sessions 75 32.10 33.16 3.30 0.380
  Completed ≥30 Sessions 55 32.16 32.03 −0.40 0.600
ASEBA (Depression/Anxiety)
  All 97 59.75 59.49 −0.44 0.583
  No Incentives 51 59.37 59.98 1.03 0.349
  Incentives 46 60.17 58.95 −2.03 0.083
  Completed <30 Sessions 48 59.56 59.13 −0.72 0.978
  Completed ≥30 Sessions 49 59.94 59.78 −0.27 0.545
SSRT
  All 98 207.80 226.06 8.79 0.333
  No Incentives 49 187.98 218.25 16.10 0.301
  Incentives 49 227.61 234.51 3.03 0.675
  Completed <30 Sessions 48 194.58 214.31 10.14 0.736
  Completed ≥30 Sessions 50 220.48 234.42 6.32 0.350
BRIEF - A
  All 105 55.90 54.48 −2.54 0.039
  No Incentives 54 55.46 56.00 0.97 0.494
  Incentives 51 56.37 52.86 −6.23 <0.001
  Completed <30 Sessions 54 56.13 54.76 −2.44 0.324
  Completed ≥30 Sessions 51 55.67 54.28 −2.50 0.076
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Table shows the change in secondary outcomes between the baseline and 4-month assessment. Changes are shown for the entire study sample (“All”) as well as broken down by study condition and by whether the patient completed 30+ sessions. BMI = body mass index. ASEBA = Achenbach System of Empirically Based Assessment. BRIEF-A = Behavioral Rating Inventory of Executive Function - Adult. GEC = Global Executive Composite. D-KEFS = Delis-Kaplan Executive Function System. SSRT = Stop Signal Reaction Time.

Socio-cognitive Characteristics

There were no significant changes in the combined measure of anxiety and depression symptomology (ASEABA depression/anxiety scale), although there was a trend towards symptom reductions in the incentive condition (p = 0.083) (Table 2). The objective measure of ExecF (SSRT) did not change significantly in this sample. However, self-reported scores of ExecF (BRIEF) improved significantly in the incentive condition (p < 0.001). No other variable examined significantly predicted changes in cognitive outcomes.

Hospital Utilization

Number of times patients contacted the hospital system (hospitalization or ED visit) ranged from 0–21, with a median of 1 and a mean of 2.05 (Figure 3). Over half of the sample (60.8%) entered the hospital system at least once during the year following their initial event. Number of hospital contacts was lower in those who completed CR (1.36 vs. 2.55 p = 0.012) with a trend for fewer contacts in the incentive condition (1.62 vs. 2.48, p = 0.079). No other variable examined significantly predicted hospital contacts.

Figure 3: Hospital Contacts:

Figure 3:

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Number of hospital contacts (hospitalizations and ED visits) by study condition and by completion status (<30 sessions completed vs. ≥30). Graphs show the number of participants with zero contacts and number of contacts within those who had hospital contacts.

Cost Analyses

Mean earnings in the incentive group were $716 per patient (CI: $694–740). Additional CR sessions received by incentives patients cost the healthcare system $1,730 (CI: $1,057–2,388) or $222 (CI: $183–421) per additional session completed. The added EDLYG by incentives patients was 0.1809 (CI: 0.0243–0.3324). The preliminary ICER was $9,336 (CI: $6,471–27,085) per life year added.

Discussion

Financial incentives increased the mean number of CR sessions completed and almost doubled completion rates among lower-SES patients for whom outpatient CR was medically indicated. Given the paucity of research on successful interventions to increase sessions of CR attended generally, and the near non-existent literature among lower-SES patients in particular, these results are very promising. Additionally, given the high-risk nature of this population as demonstrated by high rates of current smoking, psychiatric comorbidities, and hospital usage, improving CR attendance has the potential to make significant differences in longer-term health outcomes.

Completion of CR is an especially important outcome as completers show multiple health benefits compared with non-completers. In one study of over 13,000 patients with diabetes mellitus, those who completed CR had reduced mortality rates (HR 0.55), hospitalizations (HR 0.91), and cardiac-specific hospitalizations (HR 0.78) compared to non-completers, even after adjusting for demographics and presence/severity of medical conditions(20). Other studies have found CR completion to be associated with a lower mortality risk (adjusted HR of 0.59), all cause hospitalization (adjusted HR 0.77), and cardiac-related hospitalization (adjusted HR 0.68)(36). These findings are mirrored in the current trial, where CR completion was significantly associated with reduced hospitalization usage. CR completion is also associated with improvements in quality of life(37) and cognitive improvements(38), areas where positive trends were seen in the current study.

Several aspects of CR can help explain effects on hospital contacts(1). First, upon starting CR patients are assigned to a case-manager. Second, at each session, patients are weighed, vital signs assessed, and patients are queried about symptoms, risk-related behaviors (e.g. smoking), and medication concerns. This repeated clinical contact allows for behavioral intervention, symptom monitoring, and early referral to treating physician, as necessary, which can reduce hospitalizations by keeping symptoms in check, halting escalation of symptoms, and preventing unnecessary ED visits.

Preliminary cost analyses excluded two offsetting effects: CR savings in hospitalizations and medical care of added life years. Nevertheless, the results suggest that the incentives intervention was inexpensive in relation to its expected health gains. As its ICER ($9,336) was only one sixth of the 2017 US per capita gross national income ($58,270)(39) this intervention was “very” cost-effective(40) and almost an order of magnitude more cost-effective than increasingly used implantable cardioverter defibrillators (ICER: $37,031–$138,458)(41).

Characteristics of the population may help explain why incentives were necessary and successful. Executive function (ExecF), the ability to plan and undertake complex tasks and other higher-order functions, is a reliable predictor of accessing and completing health-care regimes(42). Lower-SES populations are more likely to have ExecF deficits(43); indeed, 40% of participants in this study reported ExecF difficulties. One aspect of ExecF difficulties more common in lower SES patients is a bias for the present wherein individuals disproportionately weigh the relatively immediate and tangible costs of adhering to medical regimens over the delayed and relatively intangible but more substantive benefits of adherence(44). Incentives can harness these present-biased preferences by providing immediate, tangible positive outcomes (earning incentives) for adhering with medical regimens (attending CR sessions)(45). In this trial, participants in the incentive condition also reported improvements in ExecF, a finding that suggests they may experience improvements in self-care that extend beyond the intervention.

Limitations

Several study limitations merit mention. This study was conducted at a single clinical site with a fairly racially homogenous patient population. Baseline assessments were conducted at the CR program, which may have inflated CR participation rates in the control condition. Clinical staff could not be fully blinded to patient assignment, which may have affected staff/patient interactions, although staff followed standardized protocols for promoting attendance independent of condition assignment. Hospitalizations outside of the University of Vermont Medical Center system may have been missed. Finally, sample size was determined based on the power needed to demonstrate effects of incentives on CR attendance. Studying effects of incentives on health outcomes such as fitness, psycho-cognitive parameters, hospital utilization, and more comprehensive cost-effectiveness would require a larger sample. For example, post-hoc analyses suggest a study would require 180 per condition to be powered for fitness effects and 335 for cardiac-specific QoL.

Conclusions

Financial incentives improve CR participation and completion in lower-SES, high-risk cardiac patients. Increasing access to CR in such high-risk cardiac populations is critically important to decreasing health disparities. Examining the reliability and generalizability of this effect appears warranted.

Perspectives.

Competency in Medical Knowledge:

Financial incentives improve CR participation among lower-SES patients.

Competency in Patient Care:

Lower-SES patients are at high risk for recurrent events and rehospitalization yet are much less likely to attend and complete CR. Therefore lower-SES patients may require intense intervention to increase CR participation.

Translational Outlook 1:

While lower-SES patients who completed CR had fewer ED visits and hospitalizations, larger trials with a longer follow-up period will be required to experimentally demonstrate the health and care service utilization benefits of increased CR participation.

Translational Outlook 2:

Attendance at CR is unsatisfactory in lower-SES patients. As incentives have been shown to substantially increase CR participation in this high-risk population the acceptability and feasibility of integrating an incentives-based approach into clinical care should be explored.

Acknowledgments

Clinical Trials Registration: Clinicaltrials.gov registration number: NCT02172820

Funding/Support: This research was supported in part by National Institutes of Health Center of Biomedical Research Excellence award P20GM103644 from the National Institute of General Medical Sciences.

Abbreviations:

CR

Cardiac rehabilitation

ExecF

Executive Function

SES

Socio-economic status

ED

Emergency department

BMI

Body mass index

PVO2

Peak oxygen uptake

EDLYG

Expected discounted life years gained

ICER

Incremental cost-effectiveness ratio

Footnotes

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Conflict of Interest Disclosures: All authors have no conflicts to disclose.

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