Impact of obesity on the clinical outcomes of patients undergoing pacemaker insertion during hospitalization: An analysis of the United States National Inpatient Sample

Funding Acknowledgements Type of funding sources: None. 1. Introduction Obesity causes significant cardiovascular morbidity. Nonetheless, there is also evidence supporting obesity paradox particularly in heart failure patients. The impact of obesity on the outcomes of patients undergoing pacemaker insertion is not well studied. 2. Purpose The purpose of this study is to determine if obesity paradox exists for the patients who undergo pacemaker insertion. 3. Methods Data were extracted from the National Inpatient Sample (NIS) 2016 - 2018 Database. The NIS was searched for patients who underwent pacemaker insertion while hospitalized. The patients were divided into two groups based on presence or absence of obesity as secondary diagnosis using ICD-10 codes. The primary outcome was inpatient mortality. Multivariate logistic and linear regression analysis was used accordingly to adjust for confounders. STATA software was used to for analysis. 4. Results Of 408,040 patients who underwent pacemaker insertion, 64185 (15.7%) were obese. The adjusted odds ratio for inpatient mortality for obese patient undergoing pacemaker insertion compared to non-obese patients was 0.65 (95% CI 0.516 – 0.821, p < 0.001). Secondary outcomes are listed in table 1. 5. Conclusion Obese patients who underwent pacemaker insertion had lower inpatient mortality compared to non-obese patients. Also, obese patients undergoing pacemaker insertion were less likely to have cardiac arrest but they were more likely to develop decompensated heart failure and acute renal failure compared to non-obese patients. Outcome Without Obesity, % With Obesity, % aOR (95% CI) p-value* Primary outcome In hospital mortality 10.8 7.0 0.65 (0.516 - 0.821) <0.001* Secondary outcomes Length of stay (days), mean 5.7 6.3 0.031 (-0.105 - 0.168) # 0.654 Total hospital charges (US$), mean 121250 134757 720 (-2307 - 3747) # 0.641 Decompensated heart failure 13.3 19.2 1.53 (1.451 - 1.629) <0.001* Cardiogenic shock 2.3 2.7 1.00 (0.883 - 1.141) 0.954 IABP placement 0.5 0.6 0.98 (0.746 - 1.294) 0.898 Cardiac arrest 4.27 4.30 0.83 (0.753 - 0.920) <0.001* Acute renal failure 20.7 25.4 1.17 (1.112 - 1.231) <0.001* Abbreviations: *; statistically significant, #; adjusted mean difference, aOR: adjusted odds ratio, CI: confidence interval, IABP: Intra-aortic balloon pump.Adjusting factors: Age, race, Charlson comorbidity index, primary insurance, median household income for patient’s zip code, location and teaching status of the admitting hospital, dyslipidemia, chronic obstructive pulmonary disease, hypertension, peripheral vascular disease, diabetes mellitus, chronic kidney disease, liver disease and smoking status. Table 1: Clinical outcomes of hospitalizations for pacemaker insertion based on presence or absence of obesity, analysis of United States National Inpatient Sample from 2016 through 2018.