Cardiovascular disease burden in cancer patients from 2003 to 2014

As per 2015 national report, cardiovascular disease (CVD) and cancer accounted for almost 63% of deaths. With dynamic progress in therapeutic strategies along with improving prognosis and cancer survivorship, CVD and related comorbidities is increasingly becoming a barrier to improvement in quality of life and outcomes of cancer patients. However, contemporary data describing CVD and its major risk factors in cancer are lacking. Hence, we studied the national inpatient sample databases (NIS) from 2003 to 2014 to describe the trends of 16 529 061 cancer hospitalizations. All adult patients with cancer comorbidity, who were hospitalized for any cause, were identified in NIS database.1 As shown in Table 1, disease burden was calculated by identifying both new and pre-existing diseases such as hypertension, smoking, dyslipidaemia, diabetes mellitus, coronary heart disease, heart failure, atrial fibrillation/flutter, peripheral artery disease, heart valve disorder, cerebrovascular disease, and thrombo-embolic disorders, using The International Classification of Diseases, Ninth Revision, Clinical Modification codes.2Table 2 shows hospitalization rates (HRs) were calculated in terms of 100 000 persons/calendar year using census data [https://www.census.gov/popclock/data_tables.php? component=pyramid (July 15 2017, date last accessed)]. We created different categories for risk factors and CVD burden, with ‘category 0’ representing those with no disease burden and highest category with all risk factors or all CVD as applicable. We also analysed HRs for patients with at least three risk factors (Category 3 or higher) along with one CVD (category 1 or higher), as they are more likely to require a cardiology follow-up. (Table 2) For trend analysis, we used the χ2 test in SPSS 23.0 (IBM Corp., Armonk, NY, USA) with significance threshold of P < 0.001 for two-sided P-values. Cardiovascular and related comorbidities of patients with cancer, 2003–14 All Ptrend < 0.001. CHD, coronary heart disease; PAD, peripheral arterial disease; VTE, venous thrombo-embolic disorder. Cardiovascular and related comorbidities of patients with cancer, 2003–14 All Ptrend < 0.001. CHD, coronary heart disease; PAD, peripheral arterial disease; VTE, venous thrombo-embolic disorder. Hospitalization rates (per 100 000 persons) for cancer patients stratified by number of risk factors and cardiovascular diseases, 2003–14 All Ptrend < 0.001. Based on presence of hypertension, smoking, dyslipidaemia, and diabetes; 0—none, 1—one risk factor, 2—two risk factors, 3—three risk factors, and 4—four risk factors. Based on presence of coronary heart disease, heart failure, atrial fibrillation, peripheral arterial disease, and heart valve disorders; 0—none, 1—one CVD, 2—two CVD, 3—three CVD, 4—four CVD, and 5—five CVD. CVD, cardiovascular diseases. Hospitalization rates (per 100 000 persons) for cancer patients stratified by number of risk factors and cardiovascular diseases, 2003–14 All Ptrend < 0.001. Based on presence of hypertension, smoking, dyslipidaemia, and diabetes; 0—none, 1—one risk factor, 2—two risk factors, 3—three risk factors, and 4—four risk factors. Based on presence of coronary heart disease, heart failure, atrial fibrillation, peripheral arterial disease, and heart valve disorders; 0—none, 1—one CVD, 2—two CVD, 3—three CVD, 4—four CVD, and 5—five CVD. CVD, cardiovascular diseases. As shown in Tables 1 and 2, overall HRs increased by 16% (503–602, P < 0.001) along with significant increase of all CVD and risk factors. Every year more patients survived the hospitalizations, with in-hospital mortality decreasing significantly (8.0–6.4%, P < 0.001). Also while HRs without any risk factor burden decreased by 44% (224–125), there was a significant increase in all other categories. Similarly, there was a significant increase in HRs of all CVD burden categories. Notably, HRs of patients with at least one CVD and three risk factors increased by almost 5.8 times (1–75, P < 0.001). Our report for the first time describes the increase of CVD in hospitalized cancer patients at a national level. This demands urgent mitigation at both primary and secondary prevention level as these diseases lead to under-treatment and poorer outcomes in patients undergoing cancer treatment and cancer survivors.3 A recent study showed higher prevalence of CVD in cancer patients when compared with cancer-free controls.4 Also, despite widespread acceptance of this emerging challenge for healthcare system, cancer patients are frequently excluded from CVD outcome trials. Hence, possibly more research geared towards CVD in cancer patients, is required as traditional treatment recommendations might not be completely applicable in these patients. Most importantly, the presence of two complex pathologies—CVD and cancer, warrants emphasis on a multidisciplinary team approach involving cardiologists, haematologists, and oncologists, along with increased learning and training opportunities, to optimize clinical care for those with cancer and cancer survivors.3,–5 Our study has limitations, as it is a retrospective study and based on administrative database. Hence, it may be subjected to biases of observational studies and coding errors. The NIS database lacks clinical information, treatment details, and provides information at the level of admission rather than unique patient. However, these limitations might be partially compensated by the large sample size and ability to reflect national trends. In conclusion, the staggering uprise of CVD burden in cancer imposes considerations for increased awareness and research initiatives to improve outcomes in patients with cancer and co existing CVD.