Obesity Linked to Lower Short-Term Mortality in Patients With HF With Well-Nourished Status

Obesity or overweight status is associated with lower short-term mortality in patients with acute heart failure (AHF), especially among those with a well-nourished status, according to study results published in BMC Cardiovascular Disorders.

Researchers conducted a retrospective study in the US from 2001 and 2012. Data were collected from the Medical InformationMart for Intensive Care III (MIMIC-III) database. The International Classification of Diseases, Ninth Revision (ICD-9) diagnosis codes were used to identify individuals with AHF. Nutritional status was categorized based on serum albumin levels and prognostic nutritional index (PNI). Serum albumin was classified into low (<3.5 g/dL) or malnourished and high (≥3.5 g/dL) or well-nourished. PNI was categorized into high (≥38) or well-nourished and low (<38) or malnourished. Obesity or overweight status was classified based on body mass index (BMI). 

The primary study outcome was 90-day mortality.

A total of 1325 patients were enrolled in the study. The mean age was 72.4±13.1 years and52.1% of the patients being men. Of the total population, 48.7% of patients were considered well-nourished and 51.3% were considered malnourished. 

Before propensity-score matching, patients with a malnourished status demonstrated poorer clinical outcomes, including higher-in-hospital and 90-day mortality. A total of 16.5% of these patients experienced in-hospital mortality compared with 9.5% of those with a well-nourished status; and 28.7% vs 18.0%, respectively, experienced 90-day mortality (P <.001).

In addition, 90-day mortality was negatively correlated with overweight or obese status with adjusted hazard ratios (HRs) of 0.47 (95% CI, 0.30-0.74; P =.001) and 0.45 (95% CI, 0.28-0.72; P =.001) respectively. The correlation was not significant among those with a malnourished status; an HR of 1.06 was calculated for patients with overweight (95% CI, 0.75-1.50; P =.744) and 0.86 for patients with obesity (95% CI, 0.59-1.24; P =.413).

After propensity-score matching, the 90-day risk for death in patients with overweight or obesity was reduced by 50% to 58% among the well-nourished patients. In the malnourished group, overweight or obese status did not demonstrate a significant protective effect, with an HR of 1.09 (95% CI, 0.70-1.71) and an HR of 1.02 (95% CI, 0.66-0.59), respectively. 

Low PNI scores were associated with poorer clinical outcomes in the subgroup analysis. In both the high and low PNI cohorts, patients with overweight or obesity had lower in-hospital and 90-day mortality. Patients with obesity with high PNI scores had the highest cumulative survival rate. 

Because of the retrospective design of the study, a causal relationship could not be determined.

The study authors concluded, “Further exploration and validation of nutritional indicators combined with BMI in a larger population is needed to guide clinicians

on the best strategy for treatment.”