Basal insulin analogs and NPH insulin had similar rates of hypoglycemia hospital visits, glycemic control in type 2 diabetes
Researchers used data from Kaiser Permanente of Northern California to retrospectively assess patients with type 2 diabetes who initiated a long-acting insulin analog or NPH insulin between Jan. 1, 2006, and Sept. 30, 2015.
In patients with type 2 diabetes, the use of a basal insulin analog neither reduced the risk of hypoglycemia-related ED visits or hospitalization nor improved glycemic control compared to the use of human neutral protamine Hagedorn (NPH) insulin, a recent study found.
Researchers used data from Kaiser Permanente of Northern California to retrospectively assess patients with type 2 diabetes who initiated a long-acting insulin analog (e.g., glargine or detemir) or NPH insulin between Jan. 1, 2006, and Sept. 30, 2015. Participants were censored at death, loss of health plan coverage, change in insulin treatment, or the end of follow-up on Sept. 30, 2015.
The primary outcome was the time to a hypoglycemia-related ED visit or hospital admission, and the secondary outcome was change in HbA1c level within one year of initiating insulin. Results were published online on June 23 by JAMA.
Overall, 25,489 patients (mean age, 60.2 years; 46.8% women) initiated basal insulin therapy, 92% (n=23,561) of whom started with NPH insulin. The 1,928 (8%) patients who started with insulin analogs were more likely to have a greater number of comorbidities and more all-cause ED or hospital use events within the previous year. Between-group differences, including HbA1c level, were generally small, but the median copayments for insulin analogs were twice as much as for NPH insulin ($20 vs. $10, respectively).
During a mean 1.7 years of follow-up, there were 39 hypoglycemia-related ED visits or hospital admissions among patients who initiated insulin analogs (11.9 events [95% CI, 8.1 to 15.6] per 1,000 person-years) compared to 354 hypoglycemia-related ED visits or hospital admissions among those who initiated NPH insulin (8.8 events [95% CI, 7.9 to 9.8] per 1,000 person-years), a between-group difference of 3.1 events (95% CI, −1.5 to 7.7 per 1,000 person-years; P=0.07). In an analysis of 4,428 propensity score-matched participants, the adjusted hazard ratio was 1.16 (95% CI, 0.71 to 1.78) for hypoglycemia-related ED visits or hospital admissions associated with insulin analog use.
Within one year of insulin initiation, HbA1c level decreased after initiation of insulin analogs from 9.4% (95% CI, 9.3% to 9.5%) to 8.2% (95% CI, 8.1% to 8.2%) and also decreased after initiation of NPH insulin from 9.4% (95% CI, 9.3% to 9.5%) to 7.9% (95% CI, 7.9% to 8.0%), an adjusted difference-in-differences of −0.22% (95% CI, −0.09% to −0.37%) for glycemic control.
The authors noted limitations of the study, such as its observational design and differences between the patient groups despite propensity score matching. They added that they did not examine differences in nocturnal and self-reported hypoglycemia or events treated by emergency medical services that did not involve the ED or hospital. The authors concluded, “Among patients with type 2 diabetes, initiation of a basal insulin analog compared with NPH insulin was not associated with a reduced risk of hypoglycemia-related ED visits or hospital admissions or with improved glycemic control.”
An accompanying editorial pointed out that the rate of NPH insulin initiation was particularly high, at 92%, and that clinicians' greater familiarity with this insulin type may have contributed to the reduced likelihood of hypoglycemia among NPH insulin users, which may partly explain the low event rates.
The editorialists added that questions of value in insulin prescribing will continue into the foreseeable future. “Along with pursuing measures to help control increasing insulin costs, reemphasizing NPH insulin as a front-line insulin option for most patients with type 2 diabetes could begin to bend the insulin cost curve for patients and insurers,” they wrote.