Elsevier

Endocrine Practice

Volume 16, Issue 6, November–December 2010, Pages 945-951
Endocrine Practice

Original Article
Relationship Between Glycemic Control and Readmission Rates in Patients Hospitalized With Congestive Heart Failure During Implementation of Hospital-Wide Initiatives

https://doi.org/10.4158/EP10093.ORGet rights and content

ABSTRACT

Objective

To determine the relationship between inpatient glycemic control and hospital readmission in patients with congestive heart failure (CHF).

Methods

We used an electronic data collection tool to identify patients with a discharge diagnosis of CHF who underwent point-of-care glucose assessments. Timeweighted mean glucose (TWMG), hemoglobin A1c, and glycemic lability index (GLI) served as glycemic indicators, and readmission for CHF was determined at 30 days and between 30 and 90 days.

Results

The analysis included 748 patients. After adjustment for significant covariates, log-transformed increasing TWMG (odds ratio 3.3; P = .03) and log-transformed hemoglobin A1c (odds ratio 5.5; P = .04) were independently associated with higher readmission for CHF between 30 and 90 days, but not by 30 days. Renal disease, African American race, and year of hospital admission were also significantly associated with readmission, but GLI was not. There was no significant difference in TWMG when analyzed on the basis of race or renal status. We noted a decrease in TWMG (P = .004) and a trend for reduction in readmission rates between 30 and 90 days (P = .06) after hospital-wide interventions were implemented to improve glycemic control, but no significant difference was detected in GLI or hypoglycemia.

Conclusion

Increasing glucose exposure, but not glycemic variability, was associated with higher risk of readmission between 30 and 90 days in patients with CHF. Prospective studies are needed to confirm or refute these results. (Endocr Pract. 2010;16:945-951)

Section snippets

INTRODUCTION

Mixed results from randomized controlled trials in the intensive care unit (ICU) (1., 2., 3.) have triggered appeals for focused efforts to identify patient populations and disease states that are associated with increased risk of hyperglycemia-mediated harm (4). A large retrospective study demonstrated that the magnitude of the relationship between hyperglycemia and mortality depends on the admission diagnosis, with cardiac patients generally showing the highest risk (5). In the case of

METHODS

Hospital admissions between January 1, 2005, and December 31, 2006, were searched by using the Ohio State University Information Warehouse, a computerized data analysis tool that validates, cleanses, and deidentifies patient information incorporated from multiple electronic sources. Patients with a primary discharge diagnosis of CHF (defined as an International Classification of Diseases, Ninth Revision [ICD-9] code of 428.0) were identified (N = 1, 144). Only patients having a hospital length

Glycemic Variables

The primary glucose variables of interest were the total time-weighted mean glucose (TWMG), calculated as the area under the curve for glucose with use of the trapezoidal rule divided by the total time in hours, and the glycemic lability index (GLI), also corrected for time. Time-weighting, which has been described previously (3), was performed because the intervals between glucose measurements were nonuniform. Serum glucose values were excluded in order to maintain homogeneity in glucose

RESULTS

A total of 748 patients and 9, 236 glucose measurements (mean, 12.3 per patient) were included in the final analysis. The overall frequency of glucose monitoring was variable, with 94% of patients having at least 1 reading per day but only 11% having more than 3 readings per day when averaged for the entire hospital stay. A summary of demographic and clinical information is presented in Table 1. The mean glucose value was 137 ± 44.7 mg/dL, and 34.9% of patients experienced hypoglycemia (BG

DISCUSSION

The current study demonstrates that increased TWMG and A1C are associated with intermediate (30 to 90 days) but not short-term (< 30 days) readmission rates in patients with CHF, after adjustment for other important variables (Table 4). This relationship was observed despite otherwise acceptable glycemic control (18). It is possible that inpatient glycemic control is simply a surrogate for long-term glycemia (as determined by A1C), particularly because short-term readmission rates were unrelated

CONCLUSION

In summary, total glycemic exposure, but not GV, is related to higher intermediate-term readmission rates in patients with CHF. Prospective studies are needed to determine whether patients with CHF would benefit from improved glycemic control.

DISCLOSURE

The authors have no multiplicity of interest to disclose.

ACKNOWLEDGMENT

We thank the Ohio State University Information Warehouse and the Ohio State University Clinical Research Center (Award Number UL1RR025755 from the National Center for Research Resources) for assistance with data collection and analysis. This research was also supported by the National Institutes of Health grant 1K23DK080891-02. Parts of the data were presented in poster form at the 68th American Diabetes Association Scientific Sessions; June 6-10, 2008; San Francisco, California.

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