Hypoglycemia in Hospitalized Patients Hikes Mortality Risk

Mortality risks appear to be higher in hospitalized patients who experience hypoglycemia, researchers reported in the Journal of Clinical Endocrinology & Metabolism.¹

“Hypoglycemia is common among hospitalized patients with and without diabetes mellitus,” senior study author Amit Akirov, MD, of Rabin Medical Center in Petah Tikva, Israel, said in a press release.² “Our findings suggest that hypoglycemia, whether insulin-related or non-insulin related, is associated with short- and long-term mortality risk.”

For their study, Dr Akirov and colleagues evaluated 2947 patients who experienced hypoglycemia in a cohort of more than 33,000 patients hospitalized at a 1330-bed university-affiliated medical center. Medical records and the hospital’s mortality database were used to investigate the link between hypoglycemia and mortality in hospitalized patients.

Of the patients who had at least 1 blood glucose value in the hypoglycemic range, 2605 experienced moderate hypoglycemia (1011 insulin-related; 1594 non-insulin-related) and 342 experienced severe hypoglycemia (201 insulin-related; 141 non-insulin-related).

At the end of follow-up (median: 1022 days), overall mortality was 31.9%. In the control groups, mortality was 28% in the non-insulin-treated group and 42.9% in the insulin-treated group. Among those with hypoglycemia, mortality was 50.7% in the non-insulin-related hypoglycemia group and 55.3% in the insulin-related hypoglycemia group.

For patients with severe hypoglycemia vs moderate hypoglycemia, survival time after discharge was shorter. Median time was 1048 days for those with non-insulin-related hypoglycemia, 734 days for those with insulin-related hypoglycemia, 97 days for those with insulin-related severe hypoglycemia, and 35 days for those with non-insulin-related severe hypoglycemia.

The difference in mortality was most apparent in the first year after discharge, according to the data. The researchers found that 1-year mortality rates were 40% for those with non-insulin-related hypoglycemia and 41% for those with insulin-related hypoglycemia vs 62% for those with non-insulin-related severe hypoglycemia and 57% for those with insulin-related hypoglycemia.

When compared with non-insulin-treated controls, unadjusted hazard ratios (HRs) for mortality at the end of follow-up were 1.7 (95% confidence interval [CI], 1.6-1.8) for the insulin-treated control group, 2.2 (95% CI, 2.0-2.4) for the non-insulin-related hypoglycemia group, 2.5 (95% CI, 2.2-2.7) for the insulin-related hypoglycemia group, 4.2 (95% CI, 3.5-5.2) for the non-insulin-related severe hypoglycemia group, and 3.8 (95% CI, 3.2-4.5) for the insulin-related severe hypoglycemia group (P <.001 for all).

The researchers also adjusted for age, gender, smoking status, alcohol use, diabetes, hypertension, malignancy, ischemic heart disease, congestive heart failure, cerebrovascular disease, and chronic renal failure. After adjustment, HRs for mortality at the end of follow-up were 1.8 (95% CI, 1.7-2.0) for the insulin-treated control group, 2.1 (95% CI, 1.9-2.2) for the non-insulin-related hypoglycemia group, 2.4 (95% CI, 2.1-2.6) for the insulin-related hypoglycemia group, 3.2 (95% CI, 2.6-3.8) for the non-insulin-related severe hypoglycemia group, and 3.6 (95% CI, 3.1-4.3) for the insulin-related severe hypoglycemia group (P <.001 for all).

Results showed that in patients without diabetes, adjusted HRs for mortality at the end of follow-up were 2.3 (95% CI, 2.2-2.5) for those with non-insulin-related hypoglycemia and 3.9 (95% CI, 2.9-5.2) for those with non-insulin-related severe hypoglycemia, as compared with non-insulin-treated controls (P <.001 for both). In patients with diabetes, adjusted HRs were 1.6 (95% CI, 1.4-1.9) for those with non-insulin-related hypoglycemia and 2.7 (95% CI, 2.0-3.8) for those with non-insulin-related severe hypoglycemia, as compared with non-insulin-treated controls (P <.001 for both).

The link between glucose levels and mortality appeared to be unaffected by cause of hospital admission.

“These data are a timely reminder that hypoglycemia of any cause carries the association with increased mortality,” Dr Akirov said.

The study has several limitations, the researchers noted, including:

• The assumption that hypoglycemia in insulin-treated patients was insulin-associated despite a lack of information about the temporal relation between insulin injection and hypoglycemia
• The clinical presentation of hypoglycemia was not recorded in the database
• Medical records served as the sole basis for data on comorbidities
• Smoking and alcohol habits were self-reported
• Probability of detecting hypoglycemia was higher in patients with history of hyperglycemia or hypoglycemia because they were more likely to have their blood glucose measured more frequently

Disclosures: The researchers report no conflicts of interest.

References

1. Akirov A, Grossman A, Shochat T, Shimon I. Mortality among hospitalized patients with hypoglycemia: insulin-related and non-insulin related. J Clin Endocrinol Metab. 2016 Nov 17. doi:10.1210/jc.2016-2653 [Epub ahead of print].
2. Low blood glucose levels in hospitalized patients linked to increased mortality risk [press release]. Washington, DC: Endocrine Society News Room; November 17, 2016. Accessed November 30, 2016.