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Interact CardioVasc Thorac Surg 2008;7:813-818. doi:10.1510/icvts.2008.178095 © 2008 European Association of Cardio-Thoracic Surgery
Prospective assessment of quality of life of octogenarians after cardiac surgery: factors predicting long-term outcome
a Department of Cardiothoracic Surgery, Helsinki University Hospital, Helsinki, Finland Received 15 February 2008; received in revised form 20 May 2008; accepted 22 May 2008
*Corresponding author. Tel.: +358 17 173311; fax: +358 17 173959.
Our objective was to assess the long-term prognosis and quality of life (QoL) of elderly patients after cardiac surgery. The Nottingham Health Profile (NHP) QoL data were recorded from 104 patients who were older than 70 years at the time of primary cardiac surgery in 1993. All living patients were controlled at 15±3.2 months and 8.2±0.27 years after discharge. The 1-year, 5-year and actual survival rates were 94%, 76%, and 59%, respectively. Risk factors for death were urgency of the operation (relative risk ratio, 2.0; 95% confidence interval, 1.2–3.6), ejection fraction below 50% (2.1; 1.1–3.9), and preoperative renal failure (2.1; 1.0–4.0). Cardiac operated octogenarians took advantage from age and sex matched reference populations at 15 months in the NHP dimension of pain (P=0.001). The QoL decreased gradually during the follow-up similarly in both groups in dimensions describing energy (P=0.001), pain (P=0.003), and mobility (P=0.042). Diabetes, low energy score and high pain score at 15 months, treatment in intensive care unit >3 days, and duration of symptoms >120 days preoperatively were associated with impaired QoL. Survival and QoL were similar for cardiac operated octogenarians and age and sex matched controls at 15 months and 8.2 years after cardiac surgery.
Key Words: Quality of life; Survival; Octogenarians; Cardiac surgery
A high health-related quality of life (QoL) of patients should be one of the primary goals after surgery. This is especially important for elderly patients referred for cardiac surgery, where there are special risks related to perioperative mortality and morbidity. These risks must be related to the expected benefits of surgery, i.e. to the prospects of longer survival and improved QoL. In the case of elderly patients, the survival utility does not reflect the only intention of treatment, but the outcome of cardiac surgery must also be evaluated in terms of its impact on health-related QoL. Information on the expected QoL-benefit allows the patient to form realistic expectations regarding morbidity and mortality, as well as physical, functional, emotional, and mental welfare. For the surgeon, this information is crucial for optimal patient selection, and for society it improves planning and decision-making regarding optimal allocation of healthcare resources [1–6].
The aim of this prospective study was to evaluate the current QoL status of a population of octogenarians who had undergone cardiac surgery almost ten years earlier, at age of
2.1. Patient population Altogether 823 patients underwent cardiac surgery in the Kuopio University Hospital in 1993. The population for this study consisted of 104 consecutive patients who were older than 70 years at the time of primary open heart surgery (13%; 104/823). Of these, 60 (58%) underwent coronary artery bypass grafting (CABG), 12 (11%) isolated valve surgery, and 32 (31%) combined CABG and valve surgery. All procedures were performed in cardiopulmonary bypass. Detailed patient characteristics are given in Table 1. The study was approved by the Ethics Committee of the Kuopio University Hospital and informed consent was obtained from all patients.
2.2. Data collection and follow-up Data concerning clinical patient-related variables and QoL information were recorded longitudinally over time. First, all living patients (94%; 98/104) were invited for a visit to the cardiological outpatient department 15±3.2 months [10–19 months] after discharge. There, a physical examination was made and the patients were asked to fill in the Nottingham Health Profile (NHP) QoL questionnaire. Seven patients refused to participate, which yielded an early-term follow-up ratio of 93% (91/98). Then, in November 2001, all patients were followed up with respect to survival status. For deceased patients the cause of death was recorded (National Cause of Death Register, National Centre of Statistics). All patients living at that time (59%; 61/104) were invited for a visit to the cardiological outpatient department, and they underwent the same physical examination and QoL assessment as after the operation. Five patients could not be reached and ten refused, which yielded a long-term follow-up ratio of 75% (46/61). The average long-term follow-up time was 8.2±0.27 years [7.9–8.8 years]. The study outline is shown in Fig. 1 and the survivors' characteristics at 15 months and at 8.2 years in Table 2.
2.3. Quality of life QoL was measured with the Nottingham Health Profile (NHP) [7, 8]. The NHP is classified as a generic questionnaire and it measures health-related QoL in terms of subjective emotional, functional and social impact of chronic disease. A mean score ranging from 0–100 is calculated for each dimension. The higher the score, the greater the limitations are regarding activity or distressing social and emotional problems. Differences within the study groups over time were compared with Wilcoxon's signed-rank test for continuous variables, with the marginal homogeneity test for categorical variables, and with McNemar's test for dichotomous variables. Means and standard deviations were computed for continuous variables, and proportions were compared with the non-parametric Mann–Whitney U-test or Student's t-test, as appropriate. Late survival and time-dependent events were assessed by Kaplan–Meier's survival analysis, and the log-rank test was used for univariate analysis of mortality followed by Cox's multivariate analysis for identification of statistically significant univariate factors. Risk factors for impaired QoL were analyzed by binary logistic regression. Differences with a P-value of <0.05 were considered statistically significant.
3.1. Survival One-year, 5-year and actual survival rates were 94%, 76%, and 59%, respectively (Fig. 2). This did not differ from the predicted survival of the age and sex matched reference population (58%) after nine years (Fig. 2). Actual survival rates within the CABG, isolated valve, and combination procedure groups were 65%, 58%, and 47%, respectively (P=0.188).
3.2. Mortality risk factors Among the 17 variables that were evaluated, four turned out to be statistically significantly associated with mortality by univariate analysis. Three were associated with increased mortality by multivariate analysis: those were urgency of operation, preoperative ejection fraction <50%, and preoperative creatinine level  105 µmol/l (Table 3).
3.3. Cardiac mortality There were 18 cardiac-related deaths (42%; 18/43). Fifteen were categorized as ischemic (35%), and three as valve-related (7%) deaths. Non-fatal myocardial infarction had occurred in 8.7% of survivors who visited at the outpatient department on average 8.2 years after surgery. One patient underwent conversion to valve replacement of previous mitral repair 119 days after primary surgery. Four patients (8.7%) had received a pacemaker, and one patient (2.2%) had undergone cardiac catheterization without further interventions (Table 2). Fig. 3 shows the NHP scores of the study population together with the scores standardized to the Finnish age and sex matched adult population (65–74 years in 1993, and 75–80 years in 2002). Pain at 15 months after cardiac surgery was statistically less (P=0.001) prevalent in the study group than in the reference population, but at the 8.2 years time point the study group did not differ from the reference population in terms of any QoL dimensions. Within the study group itself, however, the scores for energy (P=0.001), pain (P=0.003), and mobility (P=0.042) were significantly poorer as compared with the 15-month time point at 8.2-year time point. The QoL scores within the CABG, isolated valve, and combination procedure groups did not differ from each other at the 15-month nor at the 8.2-year time-points.
3.6. Predictors of impaired quality of life Altogether 40 possible or known predictors of QoL were tested by logistic regression (Appendix A). Six of the 40 tested variables turned out to be statistically significantly related to QoL (Table 4). Having diabetes, low energy score and a high pain score at 15 months, treatment in an intensive care unit >3 days, and a duration of cardiac symptoms preoperatively >120 days emerged as statistically significant predictors of impaired quality of life in dimensions describing energy, sleep, pain, emotion and mobility. Using statin medication protected patients against impaired QoL concerning the dimension describing energy (Table 4).
The life expectancy of the patients who had undergone cardiac surgery at the age of 70 years was similar to the age and sex matched reference population after the long-term follow-up. Correspondingly, the QoL of patients was similar to that of the age and sex matched reference population. However, the QoL of cardiac operated elderly deteriorated uniformly with the reference population during long-term follow-up. 4.1. Long-term survival, mortality and morbidity In this study, the 1-year, 5-year and actual survival rates were 94%, 76%, and 59%, respectively. These survival rates are somewhat better than reported by Engoren and co-workers [3] who studied 103 randomly selected septuagenarians undergoing cardiac surgery in 1998–1999, and reported the 1- and 2-year survival rates of all patients 83% and 82%, respectively. In the CABG-only group, both 1- and 2-year survival rates were 90% [3]. Our survival rates are more in line with the results reported by Kolh and colleagues [9]. In their study of 220 octogenarians who were discharged from the hospital after isolated aortic valve surgery (74%) and concomitant CABG (26%), the 1-, 3-, and 5-year survival rates for the entire population were 86%, 80%, and 73%, respectively.Multivariate analysis showed that risk factors for death were urgency of operation, ejection fraction <50%, and preoperative renal failure. It has been earlier shown that age, preoperative myocardial infarction, urgency of operation, and prolonged treatment in intensive care unit are independently associated with late mortality [9]. The detrimental effect of preoperative renal failure on survival after cardiac surgery has been unambiguously reported earlier [10, 11]. It is noteworthy that, in our series, the proportion of patients who had renal failure declined over time from 25% at baseline to 17% at 15 months and to only 4% at 8.2 years (Table 2). This underscores the importance of renal failure as a predictor of an extremely poor survival outcome. 4.2. Long-term quality of life Several recent reports have addressed the question of the long-term effect of cardiac surgery on QoL in elderly patients [12, 13]. During short-term follow-up, elderly patients have derived less QoL benefit from cardiac surgery than younger patients. Järvinen and co-workers [13] found, in a study of 508 patients who had undergone CABG one year earlier, that patients aged >75 years had higher mortality and morbidity, and also a poorer QoL compared to younger patients. Similar findings have been reported by Loponen and colleagues [12]: after initial improvement in QoL, the QoL of 56 patients who were older than 75 years at the time of CABG returned to the preoperative level by 18 months after surgery. A poor long-term QoL outcome may, in the elderly, be due to the natural re-progression of the underlying cardiac disease after surgery and to the co-morbidities related to old age.4.3. Predictors of quality of life Among 40 variables, five were associated with an inferior QoL: having diabetes, low energy score and high pain score at 15 months, treatment in an intensive care unit >3 days, and preoperative symptom duration were associated with a poorer QoL in the dimensions describing energy, sleep, pain, emotion, and mobility after the long-term follow-up.The risk factors that impacted on several dimensions of QoL (>2) affected mostly physical (i.e. energy and mobility) rather than mental conditions [14]. The most significant variables associated with impaired QoL in terms of physical conditions were diabetes and a low energy score at 15 months. In contrast to earlier studies [14, 15], NYHA-class III and IV did not emerge as a significant predictor of impaired QoL, although transition from NYHA-class I/II to class III/IV was statistically significant during the 8.2 years follow-up (P=0.002). However, that transition significantly increased the need for nitroglycerin (P<0.0001) during the follow-up and this supports the notion, that the variables related to physical conditions are invariably more often affected than mental dimensions also among octogenarians. In agreement with earlier reports [9, 14], diabetes and its end-organ manifestation, renal failure, emerged as the most hazardous predictor for a poor QoL outcome. Having diabetes predicted a poor QoL in the dimensions describing energy, mobility and pain. Renal failure was associated with increased mortality. The physicians should be very careful when selecting elderly patients with diabetes and potential end-organ damage for cardiac surgery. Regarding patient selection, low energy score and high pain score at 15 months, and prolonged duration of symptoms preoperatively, reflect the fact that decision-making, whether operate or not, should be done without delay in order to achieve the most feasible surgical results in terms of long-term QoL. Interestingly, the use of statin medication protected patients for impaired energy score. We are aware of the potential restrictions of our study. One is the unavoidable loss of patients inherent to long-term follow-up studies. The loss to follow-up of only 25% in our study of elderly patients over 8.2 years of time is, on the other hand, quite small and does not invalidate the major results. Another potential limitation is, that the long-term follow-up design may fail to capture early gains of QoL benefit acquired from cardiac surgery.
The long-term QoL and survival of octogenarians who have undergone cardiac surgery at the age of 70 years is comparable to QoL and survival of the age and sex matched reference population. The QoL deteriorates mostly in physical domains.
Variables tested in logistic regression analysis to predict impaired quality of life after cardiac surgery
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Abstract
1. Introduction
