Mortality Among Patients Hospitalized With Heart Failure and Diabetes Mellitus: Results From the National Inpatient Sample 2000 to 2010

Abstract

Background: Case fatality and hospitalization rates for US patients with heart failure (HF) have steadily decreased during the past several decades. Diabetes mellitus (DM), a risk factor for, and frequent coexisting condition with, HF continues to increase in the general population.

Methods and results: We used the National Inpatient Sample to estimate overall as well as age-, sex-, and race/ethnicity-specific trends in HF hospitalizations, DM prevalence, and in-hospital mortality among 2.5 million discharge records from 2000 to 2010 with HF as primary discharge diagnosis. Multivariable logistic and Poisson regression were used to assess the impact of the above demographic characteristics on in-hospital mortality. Age-standardized hospitalizations decreased significantly in HF overall and in HF with DM. Age-standardized in-hospital mortality with HF declined from 2000 to 2010 (4.57% to 3.09%, Ptrend<0.0001), whereas DM prevalence in HF increased (38.9% to 41.9%, Ptrend<0.0001) as did comorbidity burden. Age-standardized in-hospital mortality in HF with DM also decreased significantly (3.53% to 2.27%, Ptrend<0.0001). After adjusting for year, age, and comorbid burden, males remained at 17% increased risk versus females, non-Hispanics remained at 12% increased risk versus Hispanics, and whites had a 30% higher mortality versus non-white minorities. Absolute mortality rates were lower in younger versus older patients, although the rate of decline was attenuated in younger patients.

Conclusions: In-hospital mortality in HF patients with DM significantly decreased during the past decade, despite increases in DM prevalence and comorbid conditions. Mortality rate decreases among younger patients were significantly attenuated, and mortality disparities remain among important demographic subgroups.

Keywords: diabetes mellitus; heart failure; hospitalization; mortality; risk factor.

Figure 1

Data Analysis Sequence

Figure 2

Decrease in age-standardized in-hospital mortality rate among men and women with heart failure and co-existing diabetes from 2000 to 2010. p_overall χ² <0.0001. p_{linear trend} <0.0001

Figure 3

Decrease in crude in-hospital mortality rate among patients with heart failure and co-existing diabetes in different age groups (see text) from 2000 to 2010. p_overall χ² <0.0001. p_{linear trend} <0.0001 (for each stratum)

Figure 4

Decrease in crude in-hospital mortality rate among patients with heart failure and co-existing diabetes in different age groups (see text) stratified by sex, from 2000 to 2010. p_overall χ² <0.0001. p_{linear trend} <0.0001 (for each stratum)

Figure 5

Decrease in in-hospital crude mortality rate in patients with heart failure and co-existing diabetes, by sex and ethnicity (Hispanic vs non-Hispanic), from 2000 to 2010. p_overall χ² <0.0001. p_{linear trend} <0.0001 (for each stratum)

Figure 6

Decrease in in-hospital crude mortality rate in patients with heart failure and co-existing diabetes, by race (non-Hispanic white vs. composite non-white minority) from 2000 to 2010. p_overall χ² <0.0001. p_{linear trend} <0.0001 (for each stratum)