Summary
Background
Clinical studies have shown a beneficial effect of cardiac rehabilitation (CR) on mortality.
Objective
To study the effect of CR prescription at discharge on 5-year mortality in patients with acute myocardial infarction (AMI).
Methods
Participants, from the 2005 French FAST-MI hospital registry, were 2894 survivors at discharge, divided according to AMI type: ST-segment elevation myocardial infarction (STEMI; n = 1523) and non-STEMI (NSTEMI; n = 1371). The effect of CR prescription on mortality was analysed using a Cox proportional hazards model.
Results
At discharge, 22.1% of patients had a CR prescription. Patients referred to CR were younger (62.4 vs. 67.5 years), were more frequently men and more had presented with STEMI (67.8% vs. 48.3%) than non-referred patients. Ninety-four (14.7%) deaths occurred among patients referred to CR and 585 (25.9%) among non-referred patients ( P < 0.001). After multivariable adjustment, the association between CR and mortality remained significant (hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.60–0.96). Analyses stratified by sex, age (< 60 vs. ≥ 60 years) and AMI type showed that the inverse association was stronger in men (HR 0.64, 95% CI 0.48–0.87) than in women (HR 0.95, 95% CI 0.64–1.39), in younger (HR 0.34, 95% CI 0.15–0.77) than in older patients (HR 0.84, 95% CI 0.65–1.07) and in NSTEMI (HR 0.63, 95% CI 0.46–0.88) than in STEMI (HR 0.99, 95% CI 0.69–1.40).
Conclusion
After hospitalization for AMI, referral to CR remains a significant predictor of improved patient survival; some subgroups seem to gain greater benefit.
Résumé
Contexte
Différents travaux ont montré un effet bénéfique de la réadaptation cardiaque (RC) sur la mortalité.
Objectif
Nous avons étudié l’impact sur la mortalité à 5 ans de la prescription de RC chez des patients admis pour infarctus du myocarde aigu (IM).
Méthodes
Les participants du registre hospitalier FAST-MI conduit en 2005, étaient les 2894 survivants après hospitalisation dont 1523 IM avec sus-décalage du segment ST et 1371 sans sus-décalage. L’impact de la prescription de RC sur la mortalité a été analysé en utilisant le modèle de Cox.
Résultats
À la sortie de l’hôpital, 22,1 % des patients avaient une prescription de RC. Les patients adressés en RC étaient plus jeunes (62,4 vs 67,5 ans), plus fréquemment des hommes et ont présenté plus d’IM avec sus-décalage (67,8 % vs 48,3 %) que les non-adressés. Il y a eu 94 décès (14,7 %) parmi les patients adressés en RC et 585 (25,9 %) chez les non-adressés ( p < 0,001). Après ajustement multivarié, l’association entre la RC et la mortalité reste significative (0,76 [0,60–0,96]). L’analyse stratifiée sur le genre, l’âge (< 60 vs ≥ 60 ans) et le type d’infarctus a montré que l’association était plus forte chez les hommes (0,64 [0,48–0,87]) que chez les femmes (0,95 [0,64–1,39]), chez les plus jeunes (0,34 [0,15–0,77]) que chez les plus âgés (0,84 [0,65–1,07]) et pour les IM avec sus-décalage (0,63 [0,46–0,88]) que sans sus-décalage (0,99 [0,69–1,40]).
Conclusion
Après hospitalisation pour IM aigu, la RC améliore significativement la survie des patients à moyen terme et quelques sous-groupes de patients semblent avoir un meilleur bénéfice.
Background
In France in 2009, as in other economically developed countries, cardiovascular diseases were the second most important cause of mortality after tumours , and accounted for one-third of deaths; of these, 36,539 were attributable to ischaemic heart disease. Throughout the world, according to the World Health Organization, ischaemic heart disease caused the death of 7 million people in 2011 .
Cardiac rehabilitation (CR) involves multidisciplinary management . After functional assessment of the patient, management pursues at least four aims: therapeutic education; psychosociological management; secondary prevention of cardiovascular risk factors; and controlled return to physical activities and independence. All patients who require hospitalization or invasive management after myocardial infarction should participate in a CR programme in order to change their lifestyle and improve adherence to treatment (class IIa guidelines) . In the USA, according to the American Heart Association, CR must be offered to patients with coronary disease, particularly if they have numerous modifiable risk factors .
Thanks to these measures for global patient management, CR contributes to a reduction in all-cause mortality and cardiovascular mortality, improves the level of cardiovascular risk factors (with a significant decrease in total blood cholesterol, systolic blood pressure and active tobacco use) and improves quality of life .
A meta-analysis of randomized trials of patients with ischaemic heart disease showed that compared with usual care, CR was associated with a 20% reduction in all-cause mortality and a 26% reduction in cardiovascular mortality . The significant reduction in mortality and the markedly reduced risk of hospital readmission in patients undergoing CR were found again in the latest observational and pragmatic studies .
A prospective study assessing cardiovascular risk factors after 6 months of rehabilitation reported lower blood low-density lipoprotein cholesterol concentrations and reductions in the number of patients with hypertension and active smokers.
The long-term benefit of CR in the patient with ischaemic heart disease is less well known. A Swiss study showed that functional capacities were maintained at 2 years after 1 month of rehabilitation. The GOSPEL study , which evaluated therapeutic education – now an important part of CR – showed a decrease in the rates of cardiovascular mortality and non-fatal myocardial infarction after 3 years of follow-up. The study also reported better quality of life (diet, physical exercise, psychological stress).
In France, during the past 15 years, medical management of acute coronary disease has improved greatly , resulting in a major reduction in hospital mortality . However, according to a recent study , adherence to non-pharmacological treatment is low in the medium-term, and compliance with medical treatment falls far short of perfect. A North American study showed that only two-thirds of patients took their treatment correctly, and that non-compliance multiplied the risk of death by 3.8 .
Using data from the FAST-MI registry, carried out in 2005, we evaluated over a 5-year period the maintenance of the benefit of CR in reducing mortality in a sample of patients who had presented with acute myocardial infarction (AMI) .
Methods
Participants and inclusion criteria
The objective of FAST-MI was to provide an extensive description of the management and outcomes of patients who presented with acute myocardial infarction (AMI) (both ST-segment elevation myocardial infarction [STEMI] and non–ST-segment elevation myocardial infarction [NSTEMI]) and were admitted to intensive care units, whatever the type of institution (university hospitals, public hospitals or private clinics). All consecutive adult patients aged ≥ 18 years and admitted for AMI within 48 hours of symptom onset were included. AMI was defined by elevation of troponin or creatine phosphokinase-myocardial band > 2 times the upper limit of normal, associated with at least one of the following criteria: symptoms compatible with myocardial ischaemia; new pathological Q-waves; or ST or T changes compatible with myocardial ischaemia. Iatrogenic AMI was defined as an event occurring within 48 hours of a therapeutic procedure. Patients with an AMI diagnosis invalidated in favour of another diagnosis, and those with unstable angina and no increase in cardiac biomarkers were not included.
The duration of recruitment was 31 days per centre for all patients and 2 months for patients with diabetes, between 1 October and 24 December 2005. Of the 374 centres in France that treated patients with AMI at that time, 223 (60%) participated in the study. A total of 3059 patients were included. Written informed consent was provided by each patient. The study was reviewed by the Committee for the Protection of Human Subjects in Biomedical Research of Saint-Antoine University Hospital, and the data file was declared to the Commission Nationale de l’Informatique et des Libertés. Follow-up data were collected through direct contact with the patients’ physicians, the patients or their families and the registry offices of their birthplaces. Follow-up was completed in all patients. The long-term outcome was defined as death at 5 years.
Data collection
Baseline characteristics were collected prospectively. All data were recorded on computerized case record forms by dedicated research technicians who visited each of the centres at least once a week. The research technicians were also asked to ensure that recruitment was consecutive. Previous cardiovascular and non-cardiovascular history, risk factors (smoking status, hypertension or treated hypertension, dyslipidaemia or treated dyslipidaemia, family history, diabetes mellitus), clinical course during the hospital stay (symptoms, Killip class, maximum Killip class), therapeutic management during the first 48 hours, management during the hospital stay (including percutaneous coronary interventions and thrombolysis) and treatment at discharge were recorded for each patient. Left ventricular ejection fraction (LVEF) assessed at entry and at any time during the hospital stay was recorded. The electronic case report form comprised 385 items, including medications administered before the index event, prehospital, during the first 24 and 48 hours and at hospital discharge. Doses of oral medications were recorded, as well as information on CR prescription at hospital discharge and in-hospital, 5-day, 30-day and 180-day survival.
Patient follow-up
Patient follow-up was carried out by the reference investigators in the participating institutions, by the Société française de cardiologie research team or by both. The Société française de cardiologie research team used a sequential follow-up procedure: they first consulted data on death at the registrar’s offices of the patient’s birthplace; they then wrote to the family doctors and/or cardiologists; finally, they wrote to the patients themselves. In many instances, written contact was followed by telephone interviews with the patients or their family. A specific procedure was set up to categorize the clinical events occurring during follow-up. Hospital discharge letters were systematically sought for each event leading to hospitalization or death, and were analysed by a physician from the research team. All cardiovascular events for which the final diagnosis appeared unclear were reviewed by a three-member critical events committee. Follow-up at 5 years was 94.7% complete and 157 (5.3%) patients were lost to follow-up.
Statistical methods
Data are presented as means and standard deviations for quantitative variables and percentages for categorical variables. The Chi 2 test was used to compare the distribution of qualitative variables between referred to CR and non-referred groups. When basic assumptions were not satisfied, data were subjected to Fisher’s exact test.
Mean values of quantitative variables were compared by Student’s t -test. Shapiro-Wilk’s and Levene’s tests were used to test the normality of distribution of residuals and the homogeneity of variances, respectively. When basic assumptions of Student’s t -test were not satisfied, a logarithmic transformation of the variables was done or a Wilcoxon-Mann-Whitney test was performed.
Follow-up was scheduled up to 5 years. Cumulative survival curves of patients referred to CR and non-referred were determined by the Kaplan-Meier method, and were compared using the log-rank test for the individual endpoints of all-cause mortality. The relationship between baseline variables and mortality was assessed using Cox proportional hazards regression analysis. We tested the proportionality assumption using cumulative sums of martingale-based residuals. We performed regression analyses with polynomial models (quadratic and cubic) to examine for possible non-linear relations between continuous variables and mortality. All variables associated with a P value < 0.20 in the univariate analysis were introduced into a multivariable Cox model. A backward procedure was applied to assess variables that were significantly and independently associated with mortality ( P value < 0.05). Because sex and type of acute coronary syndrome did not remain in the model, they were forced. Model assumptions were verified before analysis. All tests were two-tailed at the level of significance of 0.05. All analysis was carried out using SAS software, version 9.2 (SAS Institute, Cary, NC, USA).
Results
Of the 3059 patients who met the inclusion criteria of the FAST-MI study, 2894 (94.6%) were discharged alive from hospital, and 639 (22.1%) of these received a prescription for CR.
Patient characteristics at admission to hospital are shown in Table 1 . Patients referred to CR differed from non-referred patients: they were younger by a mean of 5 years, and nearly one-quarter of men (23.8%) were referred to CR, whereas fewer than 1 in 5 women (18.2%) were referred.
| Total ( n = 2894) | Non-referral to CR ( n = 2255) | Referral to CR ( n = 639) | P | |
|---|---|---|---|---|
| Characteristics | ||||
| Women | 899 (31.1) | 735 (32.6) | 164 (25.7) | < 0.001 |
| ≥ 75 years | 944 (32.6) | 801 (35.5) | 143 (22.4) | < 0.001 |
| ≥ 65 years | 1613 (55.7) | 1337 (59.3) | 276 (43.2) | < 0.001 |
| ≥ 60 years | 1846 (63.8) | 1510 (67.0) | 336 (52.6) | < 0.001 |
| Age (years) | 66.4 ± 14.3 | 67.5 ± 14.2 | 62.4 ± 14.0 | < 0.001 |
| Risk factors and co-morbidity | ||||
| Current smoker | 891 (30.8) | 649 (28.8) | 242 (37.9) | < 0.001 |
| Body mass index (kg/m 2 ) | 26.9 ± 4.6 | 26.8 ± 4.6 | 27.2 ± 4.5 | 0.07 |
| Family history of CHD | 692 (23.9) | 497 (22.0) | 195 (30.5) | < 0.001 |
| Personal history | ||||
| Hypertension | 1644 (56.8) | 1326 (58.8) | 318 (49.8) | < 0.001 |
| Hypercholesterolaemia | 1380 (47.7) | 1071 (47.5) | 309 (48.4) | 0.62 |
| Diabetes | 582 (20.1) | 475 (21.1) | 107 (16.7) | 0.04 |
| Renal insufficiency | 144 (5.0) | 126 (5.6) | 18 (2.8) | 0.005 |
| Respiratory diseases | 114 (3.9) | 82 (3.6) | 32 (5.0) | 0.12 |
| Stroke | 134 (4.6) | 105 (4.7) | 29 (4.5) | 0.91 |
| Peripheral artery disease | 260 (8.9) | 220 (9.8) | 40 (6.3) | 0.007 |
| Cancer | 182 (6.3) | 140 (6.2) | 42 (6.6) | 0.74 |
With regard to cardiovascular risk factors, a larger proportion of referred patients were current smokers (37.9% vs. 28.8%) and were more likely to have a family history of ischaemic heart disease (30.5% vs. 22.0%); on the other hand, they were less likely to have arterial hypertension (49.8% vs. 58.8%), diabetes (16.7% vs. 21.1%), peripheral artery disease (6.3% vs. 9.8%) or renal failure (2.8% vs. 5.6%).
Of the patients admitted for acute coronary syndromes and discharged alive from hospital, 679 (23.5%) died during the 5-year follow-up. More patients died in the non-referred group (585 deaths, 25.9%) than in the referred group (94 deaths, 14.7%) ( P < 0.001). The survival curves ( Fig. 1 ) show real and significant benefit in patients who received a prescription for CR.
Table 2 shows patients’ clinical characteristics and treatments received according to CR prescription. Patients referred to CR were more frequently admitted for STEMI (67.8%, n = 433) than for NSTEMI (32.2%, n = 206). The acute episode was markedly more serious in non-referred patients, with a higher mean Killip class and a lower LVEF. Patients referred to CR were more likely to have undergone primary angioplasty (34.5% vs. 22.2%) or thrombolysis (22.4% vs. 13.8%). Taken overall, prescription of recommended medications for coronary disease was higher in referred than in non-referred patients. Quadritherapy (statin, angiotensin-converting enzyme inhibitor, beta-blocker and antiplatelet agent) was prescribed in 52.4% of the referred group compared with 42.2% of the non-referred group.
| Total ( n = 2894) | Non-referral to CR ( n = 2255) | Referral to CR ( n = 639) | P | |
|---|---|---|---|---|
| Admission variables | ||||
| First event | 2041 (70.5) | 1540 (68.3) | 501 (78.4) | < 0.001 |
| STEMI | 1523 (52.6) | 1090 (48.3) | 433 (67.8) | < 0.001 |
| Killip class at admission | ||||
| Killip class ≥ 2 | 606 (20.9) | 494 (21.9) | 112 (17.5) | 0.02 |
| Killip class = 4 (shock) | 32 (1.1) | 25 (1.1) | 7 (1.1) | 0.98 |
| In-hospital course and complications | ||||
| Change in Killip class | ||||
| Killip class ≥ 2 | 686 (23.7) | 555 (24.6) | 131 (20.5) | 0.03 |
| Killip class = 4 (shock) | 82 (2.8) | 58 (2.6) | 24 (3.8) | 0.12 |
| LVEF | 0.03 | |||
| ≥ 40% | 2042 (70.6) | 1576 (69.9) | 466 (72.9) | |
| < 40% | 377 (13.0) | 287 (12.7) | 90 (14.1) | |
| Not recorded | 475 (16.4) | 392 (12.4) | 83 (13.0) | |
| Anterior territory | 603 (20.8) | 420 (18.6) | 183 (28.6) | < 0.001 |
| Bleeding with transfusion | 112 (3.9) | 83 (3.7) | 29 (4.5) | 0.33 |
| Stroke | 20 (0.7) | 11 (0.5) | 9 (1.4) | 0.03 a |
| Transient ischaemic attack | 12 (0.4) | 6 (0.3) | 6 (0.9) | 0.03 a |
| Procedures and management | ||||
| Primary angioplasty | 719 (24.9) | 499 (22.2) | 220 (34.5) | < 0.001 |
| Angioplasty | 1903 (65.8) | 1421 (63.0) | 482 (75.4) | < 0.001 |
| Thrombolysis treatment | 455 (15.7) | 312 (13.8) | 143 (22.4) | < 0.001 |
| Treatment at discharge | ||||
| 1. Statin | 2248 (77.7) | 1717 (76.1) | 531 (83.1) | < 0.001 |
| 2. CEI-ARA2 | 1857 (64.2) | 1407 (62.4) | 450 (70.4) | < 0.001 |
| 3. Beta-blocker | 2091 (72.3) | 1594 (70.7) | 497 (77.8) | < 0.001 |
| 4. Antiplatelet agents | 2633 (91.0) | 2029 (90.0) | 604 (94.5) | < 0.001 |
| Aspirin | 2500 (86.4) | 1919 (85.1) | 581 (90.9) | < 0.001 |
| Clopidogrel | 2179 (75.3) | 1658 (73.5) | 521 (81.5) | < 0.001 |
| Inotropic agents | 17 (0.6) | 15 (0.7) | 2 (0.3) | 0.39 a |
| Diuretic agents | 691 (23.9) | 551 (24.7) | 140 (21.9) | 0.19 |
| 1 + 2 + 3 + 4 | 1286 (44.4) | 951 (42.2) | 335 (52.4) | < 0.001 |
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