Assessment of International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) Code Assignment Validity for Case Finding of Medication-related Hypoglycemia Acute Care Visits Among Medicare Beneficiaries

Fluoroquinolones and the risk of severe hypoglycaemia among sulphonylurea users: Population-based cohort study

AIM

Fluoroquinolone-related hypoglycaemia is rare but may become clinically relevant in individuals at high baseline hypoglycaemic risk, such as patients with diabetes using sulphonylureas. Our population-based cohort study assessed whether fluoroquinolones are associated with an increased risk of severe hypoglycaemia compared with amoxicillin among patients treated with sulphonylureas.

MATERIALS AND METHODS

Using the UK's Clinical Practice Research Datalink Aurum linked to hospitalization and vital statistics data, we assembled a base cohort of patients who initiated second-generation sulphonylureas (1998-2020). The study cohort included patients initiating either fluoroquinolones or amoxicillin while on sulphonylureas. Using an intent-to-treat exposure definition, we assessed the 30-day risk of severe hypoglycaemia (hospitalization with or death because of hypoglycaemia) associated with fluoroquinolones compared with amoxicillin. Cox models estimated hazard ratios (HRs) with 95% confidence intervals (CIs) of severe hypoglycaemia after 1:5 matching on previous sulphonylurea use and propensity scores. Secondary analyses were stratified by demographics and glycated haemoglobin.

RESULTS

Overall, 143 417 patients initiated fluoroquinolones (n = 13 123) or amoxicillin (n = 130 294) while on sulphonylureas. Compared with amoxicillin, fluoroquinolones were not associated with the risk of severe hypoglycaemia (HR, 1.17; 95% CI, 0.91-1.50). Fluoroquinolones were associated with an increased risk in patients <65 years (HR, 2.90; 95% CI, 1.41-5.97) but not in those ≥65 years (HR, 1.03; 95% CI, 0.79-1.35) in stratified analyses. There was no evidence of effect modification by sex or glycated haemoglobin.

CONCLUSIONS

In patients using second-generation sulphonylureas, fluoroquinolones were not associated with an increased risk of severe hypoglycaemia compared with amoxicillin. An increased risk among younger adults is possible.

Validation of an international classification of disease, tenth revision, clinical modification (ICD-10-CM) algorithm in identifying severe hypoglycaemia events for real-world studies

AIM

The transition to the ICD-10-CM coding system has reduced the utility of hypoglycaemia algorithms based on ICD-9-CM diagnosis codes in real-world studies of antidiabetic drugs. We mapped a validated ICD-9-CM hypoglycaemia algorithm to ICD-10-CM codes to create an ICD-10-CM hypoglycaemia algorithm and assessed its performance in identifying severe hypoglycaemia.

MATERIALS AND METHODS

We assembled a cohort of Medicare patients with DM and linked electronic health record (EHR) data to the University of North Carolina Health System and identified candidate severe hypoglycaemia events from their Medicare claims using the ICD-10-CM hypoglycaemia algorithm. We confirmed severe hypoglycaemia by EHR review and computed a positive predictive value (PPV) of the algorithm to assess its performance. We refined the algorithm by removing poor performing codes (PPV ≤0.5) and computed a Cohen's κ statistic to evaluate the agreement of the EHR reviews.

RESULTS

The algorithm identified 642 candidate severe hypoglycaemia events, and we confirmed 455 as true severe hypoglycaemia events, PPV of 0.709 (95% confidence interval: 0.672, 0.744). When we refined the algorithm, the PPV increased to 0.893 (0.862, 0.918) and missed <2.42% (<11) true severe hypoglycaemia events. Agreement between reviewers was high, κ  = 0.93 (0.89, 0.97).

CONCLUSIONS

We translated an ICD-9-CM hypoglycaemia algorithm to an ICD-10-CM version and found its performance was modest. The performance of the algorithm improved by removing poor performing codes at the trade-off of missing very few severe hypoglycaemia events. The algorithm has the potential to be used to identify severe hypoglycaemia in real-world studies of antidiabetic drugs.

Pharmacologic Heterogeneity and Risk of Severe Hypoglycemia with Concomitant Use of Sulfonylureas and DPP-4 Inhibitors: Population-Based Cohort Study

Dipeptidyl peptidase-4 inhibitors (DPP-4i) interact with sulfonylureas to increase their risk of hypoglycemia. Our population-based study assessed whether intraclass pharmacologic heterogeneity among sulfonylureas (long- vs. short-acting) and DPP-4i (peptidomimetic vs. non-peptidomimetic) modifies this interaction. We conducted a cohort study using the UK's Clinical Practice Research Datalink Aurum linked to hospitalization and vital statistics data. We assembled a cohort of patients initiating sulfonylureas (2007-2020). Using a time-varying exposure definition, we assessed the risk of severe hypoglycemia (hospitalization with or death due to hypoglycemia) associated with (i) concomitant use of long-acting sulfonylureas (glimepiride and glibenclamide) with DPP-4i compared with concomitant use of short-acting sulfonylureas (gliclazide and glipizide) with DPP-4i; and (ii) concomitant use of sulfonylureas with peptidomimetic DPP-4i (saxagliptin and vildagliptin) compared with concomitant use of sulfonylureas with non-peptidomimetic DPP-4i (sitagliptin, linagliptin, and alogliptin). Time-dependent Cox models estimated confounder-adjusted hazard ratios (HRs) with 95% confidence intervals (CIs). Our cohort included 196,138 sulfonylurea initiators. During a median follow-up of 6 years, 8,576 events of severe hypoglycemia occurred. Compared with concomitant use of short-acting sulfonylureas with DPP-4i, concomitant use of long-acting sulfonylureas with DPP-4i was not associated with the risk of severe hypoglycemia (adjusted HR: 0.87, 95% CI: 0.65-1.16). Compared with concomitant use of sulfonylureas with non-peptidomimetic DPP-4i, concomitant use of sulfonylureas with peptidomimetic DPP-4i was also not associated with the risk of severe hypoglycemia (HR: 0.96, 95% CI: 0.76-1.22). Intra-class pharmacologic heterogeneity did not modify the association between concomitant use of sulfonylureas (short- vs. long-acting) and DPP-4i (peptidomimetic vs. non-peptidomimetic) and the risk of severe hypoglycemia.

Validation study of case-identifying algorithms for severe hypoglycemia using hospital administrative data in Japan

OBJECTIVE

The purpose of this study was to evaluate the performance of algorithms for identifying cases of severe hypoglycemia in Japanese hospital administrative data.

METHODS

This was a multicenter, retrospective, observational study conducted at 3 acute-care hospitals in Japan. The study population included patients aged ≥18 years with diabetes who had an outpatient visit or hospital admission for possible hypoglycemia. Possible cases of severe hypoglycemia were identified using health insurance claims data and Diagnosis Procedure Combination data. Sixty-one algorithms using combinations of diagnostic codes and prescription of high concentration (≥20% mass/volume) injectable glucose were used to define severe hypoglycemia. Independent manual chart reviews by 2 physicians at each hospital were used as the reference standard. Algorithm validity was evaluated using standard performance metrics.

RESULTS

In total, 336 possible cases of severe hypoglycemia were identified, and 260 were consecutively sampled for validation. The best performing algorithms included 6 algorithms that had sensitivity ≥0.75, and 6 algorithms that had positive predictive values ≥0.75 with sensitivity ≥0.30. The best-performing algorithm with sensitivity ≥0.75 included any diagnoses for possible hypoglycemia or prescription of high-concentration glucose but excluded suspected diagnoses (sensitivity: 0.986 [95% confidence interval 0.959-1.013]; positive predictive value: 0.345 [0.280-0.410]). Restricting the algorithm definition to those with both a diagnosis of possible hypoglycemia and a prescription of high-concentration glucose improved the performance of the algorithm to correctly classify cases as severe hypoglycemia but lowered sensitivity (sensitivity: 0.375 [0.263-0.487]; positive predictive value: 0.771 [0.632-0.911]).

CONCLUSION

The case-identifying algorithms in this study showed moderate positive predictive value and sensitivity for identification of severe hypoglycemia in Japanese healthcare data and can be employed by future pharmacoepidemiological studies using Japanese hospital administrative databases.

Concomitant Use of Sulfonylureas and β-Blockers and the Risk of Severe Hypoglycemia Among Patients With Type 2 Diabetes: A Population-Based Cohort Study

OBJECTIVE

The hypoglycemic potential of β-blockers among users of sulfonylureas, drugs that strongly increase the risk of this potentially fatal adverse effect, is not well understood. Our population-based cohort study assessed the potential association between concomitant use of sulfonylureas and β-blockers versus use of sulfonylureas alone and the risk of severe hypoglycemia.

RESEARCH DESIGN AND METHODS

Using the U.K. Clinical Practice Research Datalink Aurum, we included patients initiating sulfonylureas between 1998 and 2020, excluding those with β-blocker use in the past 6 months. Time-dependent Cox models estimated hazard ratios (HRs) with 95% CIs of severe hypoglycemia (hospitalization with or death resulting from hypoglycemia; ICD-10 codes E16.0, E16.1, and E16.2) associated with current concomitant use of sulfonylureas and β-blockers compared with current sulfonylurea use alone, adjusted for baseline confounders. We also compared current concomitant use of sulfonylureas and non-cardioselective versus cardioselective β-blockers.

RESULTS

Our cohort included 252,869 initiators of sulfonylureas (mean age 61.3 years; 43% female). Median follow-up was 7.9 years. The crude incidence rate of severe hypoglycemia was 7.8 per 1,000 per year. Concomitant use of sulfonylureas and β-blockers was associated with an increased risk of severe hypoglycemia compared with sulfonylurea use alone (HR 1.53; 95% CI 1.42-1.65). There was no difference in the risk between concomitant use of sulfonylureas and noncardioselective β-blockers and concomitant use of sulfonylureas and cardioselective β-blockers (HR 0.95; 95% CI 0.74-1.24).

CONCLUSIONS

β-blockers could further increase the risk of severe hypoglycemia when used concurrently with sulfonylureas. β-blocker cardioselectivity did not seem to play a major role in this regard.