| | Social isolation and depression predict 12-month outcomes in the “waiting for a new heart study”Presented in part at the 29th annual meeting of the International Society for Heart and Lung Transplantation, April 2009, Paris, France. published online 05 October 2009. BackgroundIdentification of modifiable psychosocial characteristics related to survival of heart transplant (HTx) candidates is needed to prevent clinical deterioration and improve prognosis. MethodsA multi-site, prospective study was conducted with 318 HTx candidates (18% female, 82% male; 53 ± 11 years of age) newly listed at 17 hospitals in Germany and Austria. Baseline demographic and psychosocial characteristics were assessed by questionnaires. Indicators of disease severity (Heart Failure Survival Score, creatinine, cardiac index) and 12-month outcomes (death, high-urgency HTx, elective HTx, de-listing due to deterioration or improvement) were provided by Eurotransplant. ResultsBy 12 months, 33 patients died, 83 received an urgent HTx, 30 underwent an elective HTx, and 9 were de-listed due to clinical deterioration and 17 due to improvement. All measures of disease severity predicted outcomes. Controlling for disease severity, the number of social contacts contributed significantly to outcomes, favoring those who improved. Comparing socially isolated patients (<4 social contacts/month) who also had depression scores in the clinical range (high psychosocial risk group; n = 37) to those with >10 social contacts/month without depression (low psychosocial risk group; n = 47) revealed significant differences in the distribution of outcome frequencies (chi-square = 11.2, df = 4, p < 0.04). The high psychosocial risk group was more likely to have died/deteriorated and less likely to have improved than the low psychosocial risk group. ConclusionsRegardless of disease severity, socially isolated HTx candidates who are also depressed may be at increased risk for clinical deterioration and mortality, indicating a need for psychosocial intervention. Donor heart shortage remains a major problem in the field of heart transplantation, resulting in an increased waiting time.1, 2 Approximately 40% of patients wait-listed for a new heart are still waiting after 1 year.3 To maximize donor heart utilization, identification of factors related to mortality or clinical deterioration while wait-listed is needed. With regard to identification of medical predictors, considerable progress has been made.4 In contrast, there is very little systematic research on psychosocial factors and their role in the prediction of outcomes. Findings from recent studies of patients at various stages of heart failure suggest that such factors are indeed related to adverse outcomes.5, 6, 7 For example, Pelle et al identified 25 prospective studies in chronic heart failure that examined mortality as an outcome and included measures of depression, social isolation, and anxiety.6 There was evidence that both depression and social isolation were associated with poor prognosis, independently of biomedical risk factors. Because of the common co-occurrence of factors measuring psychologic distress, the investigators pointed to the importance of examining the combined effects of psychologic constructs on adverse outcomes, as several other studies of coronary heart disease have done.8, 9, 10 Although the importance of psychosocial factors has been acknowledged in determination of eligibility for heart transplantation (HTx),4, 11, 12 the role of these factors in the prognosis after wait-listing remains elusive. The major aim of the ongoing “Waiting for a New Heart Study” is to identify modifiable psychosocial risk factors for poor outcome while waiting for a new heart. In this report, we investigate depression and social isolation (separately and combined) assessed at time of listing as predictors of 1-year outcomes. Methods  The “Waiting for a New Heart Study” is a prospective 2-year, multi-center observational study of patients newly listed for HTx. The study aims to identify psychosocial and behavioral predictors of pre-transplant outcomes. An invitation letter was sent to all HTx centers in Germany and Austria by Eurotransplant. Seventeen HTx centers agreed to participate. The study was approved by local ethics committees and carried out in accordance with the 2008 Declaration of Helsinki. This study presents results from the 1-year follow-up. Procedure and participants The study procedures have been described previously.13 Briefly, informed consent was obtained from patients in each center over a period of 20 months from April 2005 to December 2006. Criteria for enrollment were new registration on the wait-list (Eurotransplant identification number), not needing a combined heart–lung transplant, no re-transplant, aged >17 years, and fluency in German. A total of 479 patients were eligible. Medical screening by local physicians resulted in an additional exclusion of 99 patients, primarily because they were considered “medically unfit” (71%). Age, gender, and New York Heart Association (NYHA) class were available for excluded patients. Of the 380 patients approached, 40 declined participation. The 340 participants were mailed the psychosocial questionnaires. The questionnaires were returned by 318 patients (2 died and 2 were transplanted before completing the questionnaire, 8 withdrew their participation, and 10 did not return the questionnaire and could not be contacted, resulting in a response rate of 93.5%). The median time interval between date of listing and questionnaire return was 15 days (interquartile range 15.25, mean 19.7, SD 20.1). The entire group of non-participants (n = 161) was comparable with the 318 participating patients in terms of age and percentage of women. However, non-participants were more likely to have worse functional capacity compared with participants (51.1% vs 24.4% in NYHA Class IV).13 Measures Medical characteristics at time of listing were provided by Eurotransplant. These included date of wait-listing, diagnosis (dilated cardiomyopathy, ischemic heart disease and others), weight, height, NYHA class, hemodynamic parameters, laboratory parameters, peak oxygen consumption (Vo2max) devices (Table 1), and medications (Table 2). In this study disease severity included cardiac index, creatinine, and the Heart Failure Survival Score (HFSS).4, 14, 15 The HFSS has been developed and validated in patients undergoing HTx.14 It consists of 7 non-invasively measured prognostic variables including: mean arterial blood pressure; resting heart rate; left ventricular ejection fraction (LVEF); serum sodium; presence of intraventricular conduction delay (QRS interval ≥0.12 seconds); etiology of heart failure (ischemic vs non-ischemic); and Vo2max. Studies have indicated acceptable prognostic performance even in the era of widespread beta-blocker use.4, 16 Outcomes. Changes of wait-list status and date of change during the 12-month follow-up since date of wait-listing were provided by Eurotransplant. Based on this information, the following 6 outcome categories were considered: death; high-urgency (HU) transplantation (transplantation while listed as HU); elective transplantation; being de-listed due to clinical deterioration; being de-listed due to clinical improvement; and still waiting by the end of 12 months. Demographics data included: age; gender; disease duration; marital status; living alone/or with other(s); education (≤9 years [“Hauptschule”] vs ≥10 years [“Realschule, Fach-/Abitur”]); and currently working vs not working. Patients also noted whether they were in-patients (yes/no) at time of psychosocial assessment. Depression was assessed using the German version of the Hospital Anxiety and Depression Scale—Depression subscale (HADS-D).17 This measure includes 7 statements (eg, “I look forward with enjoyment to things” and “I feel cheerful” [both reverse scored], and “I feel as if I am slowed down”). Responses range from 0 to 3 and are added (a high score reflects more depression; maximum sum = 21). A score ≥9 suggests the presence of clinical depression.17 This cut-off was used to group participants into low- and high-depression groups. Internal consistency of the depression scale is sufficient with Cronbach's α = 0.81 in the German norm sample of 6,200 (90% cardiology) patients,17 and α = 0.77 in our sample.13 Both the English and the German version of the scale have been extensively validated.18 Network size was the patient's estimate of the “number of close friends and relatives one usually has contact with during 1 month.”19 Data analyses Analyses were conducted using both the SPSS, version 15.0 (SPSS, Inc, Chicago, IL), and SAS software. Descriptive statistics given are observed frequencies and percentages for categorical variables, and means and standard deviations for continuous variables. “Death” and “de-listing due to deterioration” were grouped into one outcome, yielding 5 outcome groups. Four patients were excluded from analyses because they were de-listed due to other reasons (3 patients withdrew consent for HTx, 1 patient's reason was undocumented). To test for group differences in demographic, medical, and psychosocial characteristics, the chi-square test or Fisher's exact test was performed for categorical variables. NYHA Classes II, II, to III and III, were condensed to II/III in order to avoid low cell counts. Ninety-four patients had missing values in at least one of the variables included in the HFSS. According to procedures used at Eurotransplant, sample medians were substituted for missing values. Single-factor analyses of variance were used to test group differences in distribution of the continuous variables. If the overall effect was statistically significant, each group was compared with the reference group “still waiting” using simple contrasts. Analyses comparing group differences in depression and network size were rerun controlling for HFSS, cardiac index, and creatinine. To compare patients with both critically high levels of depression and social isolation (high psychosocial risk group) to patients with low depression and high network size (low psychosocial risk group), we grouped patients using the suggested cut-off value for depression (≥9),17 and the lower and upper quartiles of the distribution of network size.19 These two groups were compared in baseline demographic and medical characteristics using the chi-square test, Fisher's exact test, and t-tests. Comparisons of the frequency distribution of the 5 outcomes in these 2 psychosocial risk groups were made using an overall chi-square test with 4 degrees of freedom (df). Post hoc chi-square tests with 1 df were subsequently conducted to assess which of the outcome rates were associated with a high psychosocial risk. Because we expected high psychosocial risk to be associated with unfavorable outcomes, these post hoc tests were conducted using a 1-sided alternative. All other statistical tests were 2-sided, and the significance level was set at p < 0.05. Results Wait-list outcomes By the end of 12 months, 42 patients (13.2%) had died (n = 33), or their health status had deteriorated significantly, resulting in patient de-listing (n = 9). Eighty-three patients (26.1%) were transplanted because of high urgency, 30 (9.4%) were electively transplanted, 17 (5.3%) were de-listed due to improvement in their health status, and 142 (44.7%) were still waiting for a new heart. Four patients (1.3%) had been de-listed due to other reasons. Table 1 shows demographic, medical, and psychosocial characteristics assessed at baseline for each 12-month outcome group. As expected, disease severity was related to outcome. For example, patients who died or deteriorated after 12 months had the lowest HFSS and the highest creatinine levels, which also differed significantly from the reference group “still waiting.” Patients who were de-listed due to improvement had the most favorable values in these variables, although statistically significant differences from the reference group were only observed for cardiac index, and not for HFSS and creatinine (Table 1). Only 7 patients had an implanted ventricular assist device at baseline (1 died/deteriorated, 2 HU-HTx, 2 HTx, 0 improved, 2 still waiting). There were significant differences in network size, with the clinically improved group reporting the largest average network, which even differed significantly from the reference group (Table 1). After controlling for disease severity, the p-value remained at <0.05. Average depression scores did not differ by outcome groups. However, the distribution of outcomes differed marginally (p < 0.06) by depression group, with patients depressed at baseline being underrepresented among the improved patients. Baseline medications were similar by outcome group (not shown), with the exception of anti-arrhythmics, which were more prevalent among elective HTx recipients (p < 0.02). Medications for the entire sample are given in Table 2. Combined effects of depression and social isolation Depression and network size correlated by r(318) = −0.12, p = 0.030; therefore, depression accounted for only 1.4% of the variability in network size. According to the recommended cut-off for depression,17 123 patients had scores in the clinically significant range (mean 11.6, SD 2.6, range 9 to 20). Regarding network size, 65 patients fell into the lowest quartile, with network size ranging from 0 to 3 family members or friends whom patients had contact with in 1 month (mean 2.4, SD 0.8). The highest quartile consisted of 64 patients, with social contacts ranging from 11 to 40 (mean 18.0, SD 6.3). Patients with both low network size and high depression (n = 37) were classified as the “high-psychosocial-risk” group (11.8% of the sample). Patients with both high network size and no indication of depression (n = 47) were classified as the “low psychosocial risk” group (26.8% of the total sample). Table 2 shows comparisons of baseline characteristics between the 2 psychosocial risk groups, as well as those of the entire sample for descriptive purposes. The two risk groups did not differ medically, except for diagnosis. There were more patients with ischemic cardiomyopathy in the high psychosocial risk group than in the low psychosocial risk group. Twelve-month outcomes for the psychosocial risk groups are shown in Figure 1. The significant chi-square value (p < 0.04) indicates that the outcome distribution differed for the 2 groups. Post hoc analyses using chi-square with 1 df yielded some indication that patients with high psychosocial risk were more likely to be in the died/deteriorated group after 12 months than those with low psychosocial risk (chi-square = 3.1, 1 df, p = 0.048, 1-sided). In addition, high psychosocial risk was associated with a reduced rate of improvement (chi-square = 15.8, 1 df, p = 0.004, 1-sided). Because the 2 psychosocial risk groups differed in diagnosis (ischemic etiology), we computed the partial association between psychosocial group and each of these 2 outcomes conditioning on diagnosis. The results remained significant both for death/deterioration (Cochran–Mantel–Haenszel test: chi-square = 3.06 1 df, p = 0.040, 1-sided) and improvement (Cochran–Mantel–Haenszel test: chi-square = 5.46, 1 df, p < 0.001, 1-sided), indicating that the association of each outcome rate with psychosocial risk was observed consistently across diagnoses. Discussion In this investigation we found support for the notion that psychosocial characteristics of HTx candidates at time of wait-listing are related to outcomes 1 year later, even when considering disease severity. Specifically, our findings suggest that social isolation, especially when combined with depression scores in the clinical range, may be important for the prognosis of HTx candidates. Sample characteristics at baseline were generally comparable to those observed in other studies of adult HTx candidates (eg, age, diagnosis, percent female2, 20). However, patients who were excluded from our study were more likely to have severe heart failure, resulting in fewer study participants in NYHA Class IV (24.4%). In regard to outcomes, 45% of patients wait-listed in our study were still waiting for a new heart after 1 year. The corresponding percentage reported by Eurotransplant is similar (40%).3 Six percent of our patients were de-listed due to improvement, whereas 9% were reported in the COCPIT study.21 However, mortality and clinical deterioration in our study (13.2%) were considerably lower than observed by others (COCPIT study: 22%21; Eurotransplant, German sample: 19%3). One reason for the lower mortality and clinical deterioration in our study could be that we had fewer patients in NYHA Class IV. Baseline demographics, including age, were unrelated to 12-month outcomes. As expected, several indicators of disease severity differed by outcome group. Specifically, the HFSSs were the lowest and creatinine levels the highest among patients who died or deteriorated after 12 months, whereas the most favorable values in these variables were observed among patients who were de-listed due to improvement, confirming the importance of these measures for prognosis.4, 14, 16 Most interestingly, this pattern of findings was mirrored by the results for network size. That is, network size was smallest among patients who died or deteriorated, and was largest among improved patients. This finding remained significant after controlling for HFSS, creatinine level, and cardiac index. Regarding depression, continuously measured scores were not related to wait-list outcomes. This finding is consistent with that reported in a German single-center study of HTx candidates.22 However, grouping patients according to clinically relevant cut-off scores for depression revealed a marginally significant finding, suggesting that those with scores in the clinically relevant range were least likely to have improved 12 months later. This finding, together with those based on the aforementioned group comparisons, provides some indication that depression, network size, and cardiac index may be among the variables that determine whether a patient becomes de-listed due to clinical improvement or remains on the wait-list. Considering that both depression and social isolation indicate psychosocial distress,6 we compared outcomes of patients at high psychosocial risk (ie, lowest quartile of social contacts and depression scores in the clinically depressed range) with those of patients low with psychosocial risk (ie, highest quartile of social contacts and non-depressed) for exploratory purposes. Patients in the high-risk group were more likely to have died or deteriorated and were less likely to have been de-listed due to clinical improvement by 12 months than patients in the low-risk group. Notably, the two groups did not differ in any of the medical characteristics, except for diagnosis (ie, those with high psychosocial risk were more likely to have an ischemic etiology). However, the results remained the same after controlling for diagnosis. These results are intriguing, confirming the importance of considering more than one psychosocial variable in an effort to capture psychosocial distress.6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 Social connectedness in the absence of depression may have positive effects on patients' self-esteem and sense of belonging and purpose in life, thereby facilitating health behaviors such as adherence to medication regimens.23 Several limitations of this 1-year follow-up report should be noted. First, our findings may not generalize to all patients registered for HTx within Eurotransplant, as patients who could not be included in our study were more likely to have severe heart failure as documented by NYHA class. Second, the study relied on self-reports for depression and social network size. It is conceivable that patients could present themselves as more psychologically stable in order to avoid becoming de-listed. Clinical interview assessment of depression would have been desirable to confirm depression in those with scores in the clinically relevant range. Similarly, we did not assess the nature of social networks in detail (eg, friend vs family or in-person contact vs telephone/internet). As network size denotes only one aspect of support, other aspects of support (eg, emotional support or support for engaging in health behaviors) may have additional relevance for outcomes. Finally, this report was based on the first year of a 2-year prospective study. It is expected that with the extended follow-up, statistical power will be sufficient to employ Cox proportional hazard models and a competing risk approach to take into account the independent or multiplicative effects of social network size and depression on death, transplantation, or improvement, rather than dealing with extreme cases as we have done here. We also will be able to take other factors into account, such as gender and/or living alone, as availability of social networks may be of special importance for men or for patients living alone. In conclusion, our findings linking psychosocial factors to outcomes (regardless of disease severity) after only 1 year in this 2-year prospective study clearly suggest that continued investigation of modifiable psychosocial patient characteristics holds much promise for the development of behavioral interventions in efforts to prevent clinical deterioration and improve prognosis in this patient population. Disclosure Statement The authors thank the participating centers: Med. Klinik I/Kardiologie, Pneumologie, Angiologie Universitätsklinikum Aachen (Professor Dr Kelm, Dr Koch); Herz-Zentrum Bad Krozingen (Professor Dr Neumann, Dr Zeh); Herz- und Diabeteszentrum Nordrhein-Westfalen Bad Oeynhausen (Professor Dr Körfer, Dr Schulze Schleithoff, Dr Tenderich); Herzzentrum Dresden (Professor Dr Strasser, Dr Thoms); Herzchirurgische Klinik der Universitätsklinik Erlangen (Professor Dr Weyand, Dr Tandler); Med. Klinik III/Kardiologie Klinikum der Universität Frankfurt (Professor Dr Zeiher, Dr Seeger); Klinik für Thorax-, Herz-, und Gefässchirurgie des Klinikums Fulda (Dr Dörge, Dr Weipert); Abt. Kardiologie, Universitätsklinikum Giessen und Marburg, Standort Giessen (Dr Heidt, Dr Stadlbauer) Klinik für Chirurgie der Medizinischen Universität Graz/University of Graz (Professor Dr. Tscheliessnigg, Dr Kahn); Universitätsklinik und Poliklinik für Herz- und Thoraxchirurgie Halle-Wittenberg (Professor Dr Silber, Dr Friedrich, Dr Hofmann); Universitäres Herzzentrum Hamburg GmbH (Professor Dr Reichenspurner, Dr Meffert, Dr Wagner); Klinik für Herz-, Thorax-, und Gefässchirurgie des Universitätsklinikums Jena (Professor Dr Gummert, Dr Malessa, Dipl.-Psych. Tigges-Limmer); Klinik und Poliklinik für Herz- und Thoraxchirurgie der Universität zu Köln (Professor Dr. Wahlers, Dr Müller-Ehmsen); Klinik für Herzchirurgie des Herzzentrums Leipzig GmbH (Professor Dr Mohr, Dr Doll); II. Medizinische Klinik und Poliklinik Universitätsmedizin Mainz (Professor Dr Münzel, Dr Koniordos); Herzchirurgische Klinik der Universität München (Professor Dr Reichart, Dr Kaczmarec); Klinik und Poliklinik für Herz-, Thorax-, und herznahe Gefässchirurgie der Universität Regensburg (Professor Dr Schmid, Dr Rupprecht, Professor Dr Birnbaum). Supported by the Alexander von Humboldt Foundation (G.W.), Eurotransplant International Foundation, German Academic Exchange Service (G.W.), German Research Foundation (Grant Nos. SP945/1-1 and SP945/1-3 to H.S. and MA 155/75-1 (and SP945/1-1 and SP945/1-3, respectively) to G.W.), and Johannes Gutenberg University Mainz (H.S.). None of the authors has any conflicts of interest to disclose. References 1. 1Oosterlee A, Rahmel A, van Zwet W. Eurotransplant International Foundation annual report 2006. Leiden: Eurotransplant Foundation; 2007;. 2. 2Taylor DO, Edwards LB, Aurora P, et al. Registry of the International Society for Heart and Lung Transplantation: twenty-fifth official adult heart transplant report—2008. J Heart Lung Transplant. 2008;27:943–956. Full Text |
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3. 3Smits JMA, Vanhaecke J, Haverich A, et al. Waiting for a thoracic transplant in Eurotransplant. Transplant Int. 2006;19:54–66. 4. 4Mehra MR, Kobashigawa J, Starling R, et al. Listing criteria for heart transplantation: International Society for Heart and Lung Transplantation guidelines for the care of cardiac transplant candidates—2006. J Heart Lung Transplant. 2006;25:1024–1042. Full Text |
Full-Text PDF (231 KB)
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5. 5Friedmann E, Thomas SA, Liu F, et al. Relationship of depression, anxiety, and social isolation to chronic heart failure outpatient mortality. Am Heart J. 2006;152:940;. Abstract | Full Text |
Full-Text PDF (132 KB)
6. 6Pelle AJ, Gidron YY, Szabo BM, et al. Psychological predictors of prognosis in chronic heart failure. J Card Fail. 2008;14:341–350. Abstract | Full Text |
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7. 7Tsuchihashi-Makaya M, Kato N, Chishaki A, et al. Anxiety and poor social support are independently associated with adverse outcomes in patients with mild heart failure. Circulation. 2009;73:280–287. 8. 8Angerer P, Siebert U, Kothny W, et al. Impact of social support, cynical hostility and anger expression on progression of coronary atherosclerosis. J Am Coll Cardiol. 2000;36:1781–1788. Abstract | Full Text |
Full-Text PDF (188 KB)
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9. 9Boyle SH, Michalek JE, Suarez EC. Covariation of psychological attributes and incident coronary heart disease in U.S. Air Force veterans of the Vietnam War. Psychosom Med. 2006;68:844–850.
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10. 10Knox SS, Adelman A, Ellison RC, et al. Hostility, social support, and carotid artery atherosclerosis in the National Heart, Lung, and Blood Institute Family Heart Study. Am J Cardiol. 2000;86:1086–1089. Abstract | Full Text |
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11. 11Deng MC, Smits JMA, Packer M. Selecting patients for heart transplantation: which patients are too well for transplant?. Curr Opin Cardiol. 2002;17:137–144. MEDLINE |
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12. 12Olbrisch ME, Benedict SM, Ashe K, et al. Psychological assessment and care of organ transplant patients. J Consult Clin Psychol. 2002;70:771–783.
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13. 13Spaderna H, Weidner G, Zahn D, et al. Psychological characteristics and social integration of patients with ischemic and non-ischemic heart failure newly listed for heart transplantation: the Waiting for a New Heart Study. J Appl Psychol Health Well-Being. 2009;1:188–210. 14. 14Aaronson KD, Schwartz JS, Chen TM, et al. Development and prospective validation of a clinical index to predict survival in ambulatory patients referred for cardiac transplant evaluation. Circulation. 1997;95:2660–2667. MEDLINE 15. 15Lund LH, Aaronson KD, Mancini DM. Validation of peak exercise oxygen consumption and the Heart Failure Survival Score for serial risk stratification in advanced heart failure. Am J Cardiol. 2005;95:734–741. Abstract | Full Text |
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16. 16Lund LH, Aaronson KD, Mancini DM. Predicting survival in ambulatory patients with severe heart failure on beta-blocker therapy. Am J Cardiol. 2003;92:1350–1354. Abstract | Full Text |
Full-Text PDF (114 KB)
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17. 17Herrmann-Lingen C, Buss U, Snaith RP. HADS-D Hospital Anxiety and Depression Scale—German version (A questionnaire to assess anxiety and depression in somatic medicine). 2nd ed.. Bern: Huber; 2005;. 18. 18Herrmann C. International experiences with the Hospital Anxiety and Depression Scale—a review of validation data and clinical results. J Psychosom Res. 1997;42:17–41. Abstract |
Full-Text PDF (1714 KB)
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19. 19Frasure-Smith N, Lesperance F, Gravel G, et al. Social support, depression, and mortality during the first year after myocardial infarction. Circulation. 2000;101:1919–1924. 20. 20Molzahn M, Tuffs A, Vollmann J. Organ transplantation and organ donation. Berlin: Robert Koch Institut; 2003;. 21. 21Deng MC, De Meester JMJ, Smits JMA, et al. Effect of receiving a heart transplant: analysis of a national cohort entered on to a waiting list, stratified by heart failure severity. BMJ. 2000;321:540–545. 22. 22Zipfel S, Schneider A, Wild B, et al. Effect of depressive symptoms on survival after heart transplantation. Psychosom Med. 2002;64:740–747. MEDLINE |
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23. 23Lett HS, Blumenthal JA, Babyak MA, et al. Social support and coronary heart disease: epidemiologic evidence and implications for treatment. Psychol Med. 2005;67:869–878. a Psychological Institute, Johannes Gutenberg University, Mainz, Germany b Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York c Department of Transplantation Surgery, Medical University, Graz, Austria d Eurotransplant International Foundation, Leiden, The Netherlands e Department of Biology, San Francisco State University, San Francisco, California  Reprint requests: Heike Spaderna, PhD, Psychological Institute, Johannes Gutenberg-Universität Mainz, Binger Strasse 14-16, 55099 Mainz, Germany. Telephone: 0049-6131-39-39166. Fax: 0049-6131-39-39154
PII: S1053-2498(09)00614-7 doi:10.1016/j.healun.2009.07.018 © 2010 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved. | |
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