Calculated Daily Insulin Dosages Overestimate Prescribed Insulin Doses in Type 2 Diabetes: A Primary Care Database Study

Abstract

Background:The aim was to compare the prescribed and calculated daily insulin dosages based on prescription data in type 2 diabetes patients in a general practice database. Methods:A total of 17 782 type 2 diabetes patients (age: 70.0 ± 11.5 years; 52% males; 16% diabetologist care) with ≥2 insulin prescriptions from 834 practices were analyzed (Disease Analyser: 01/2011-12/2015. Prescribed daily dosage (PDD) (physician documentation) and calculated daily dose (CDD) (pack size × strength × volume / days between 2 prescriptions) were calculated for short-acting, long-acting, and premixed insulins. PDD and CDD were compared using paired t-tests. Linear regression models assessed the associations of insulin dosage difference (CDD-PDD) with age, sex, diabetologist care, private health insurance, obesity, HbA1c, hypertension, hyperlipidemia, macro-and microvascular complications. Results: Mean [SD] CDDs were higher than PDDs for short-acting (52 [28] vs 48 [26] units/day), long-acting (30 [20] vs 24 [15] units/day), and premixed (46 [26] vs 40 [21] units/day) insulins (all P < .05). In regression models, age (per year) was associated with higher CDD-PDD differences (+0.11, +0.04, +0.10; P < .01) for short-, long-acting, and premixed insulins, respectively. Diabetologist care was related to lower differences (-2.92, -1.02, -3.65; all P < .05). HbA1c was associated with higher differences in long-acting and premixed insulins, but was related to a lower difference in short-acting insulins (all P < .05).Conclusions: CDD in primary care database studies substantially overestimate the PDD (8-25%). Age, diabetologist care, and glycemic control were related to CDD-PDD differences. Priming and safety shots with pens, dosing errors, or the accumulation of insulin reserves by patients may be underlying reasons.

Slow Titration and Delayed Intensification of Basal Insulin Among Patients with Type 2 Diabetes

“…Calculated daily dose of insulin may overestimate prescribed daily dose; therefore, it is likely that the treatment inertia we observed occurs to an even greater extent. 30 We evaluated first occurrence of treatment intensification among uncontrolled patients and included a calculated increase in basal insulin dose as a treatment intensification strategy. Most patients intensified treatment during the follow-up; however, most failed to achieve glycemic targets thereafter.…”

No effects of the COVID-19 pandemic on the prescription of insulin in Germany

“…However, the study results should be interpreted in light of two limitations. First, CDD may overestimate prescribed insulin doses [12] , and this may have biased the analyses. Second, only prescriptions reimbursed by statutory health insurance funds are documented in the LRx database, and the findings may not be generalized to Germany.…”

Patterns of insulin therapy and insulin daily doses in children and adolescents with type 1 diabetes in Germany

“…The CDD is an estimated insulin dose that is not documented by an HCP. Therefore, it is inaccurate and usually about 20% higher than the actual insulin dose 26 . Unfortunately, the database used does not include any information on training and educational aspects, for example, with respect to insulin dose calculators.…”