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.

Sodium-glucose cotransporter-2 inhibitors for hypergycemia in phosphoinositide 3-kinase pathway inhibition.

PURPOSE: Phosphoinositide 3-kinase (PI3K) inhibition is used for the treatment of certain cancers, but can cause profound hyperglycemia and insulin resistance, for which sodium-glucose cotransporter-2 (SGLT2) inhibitors have been proposed as a preferred therapy. The objective of this research is to assess the effectiveness and safety of SGLT2 inhibitors for hyperglycemia in PI3K inhibition. METHODS: We conducted a single-center retrospective review of adults initiating the PI3K inhibitor alpelisib. Exposure to different antidiabetic drugs and adverse events including diabetic ketoacidosis (DKA) were assessed through chart review. Plasma and point-of-care blood glucoses were extracted from the electronic medical record. Change in serum glucose and the rate of DKA on SGLT2 inhibitor versus other antidiabetic drugs were examined as co-primary outcomes. RESULTS: We identified 103 patients meeting eligibility criteria with median follow-up of 92 days after starting alpelisib. When SGLT2 inhibitors were used to treat hyperglycemia, they were associated with a decrease in mean random glucose by -46 mg/dL (95% CI - 77 to - 15) in adjusted linear modeling. Five cases of DKA were identified, two occurring in patients on alpelisib plus SGLT2 inhibitor. Estimated incidence of DKA was: alpelisib plus SGLT2 inhibitor, 48 DKA cases per 100 patient-years (95% CI 6, 171); alpelisib with non-SGLT2 inhibitor antidiabetic drugs, 15 (95% CI 2, 53); alpelisib only, 4 (95% CI 0.1, 22). CONCLUSIONS: SGLT2 inhibitors are effective treatments for hyperglycemia in the setting of PI3K inhibition.

Exocrine Pancreatic Insufficiency Induced by Immune Checkpoint Inhibitors.

BACKGROUND: Scant data describe exocrine pancreatic insufficiency (EPI) secondary to immune checkpoint inhibitor (ICI) use. The goal of this study is to describe the incidence, risk factors, and clinical characteristics of patients with ICI-related EPI. PATIENTS AND METHODS: A single center, retrospective case-control study was performed of all ICI-treated patients at Memorial Sloan Kettering Cancer Center between January 2011 and July 2020. ICI-related EPI patients had steatorrhea with or without abdominal discomfort or weight loss, started pancrelipase after initiation of ICI, and demonstrated symptomatic improvement with pancrelipase. Controls were matched 2:1 by age, race, sex, cancer type, and year of ICI start. RESULTS: Of 12 905 ICI-treated patients, 23 patients developed ICI-related EPI and were matched to 46 controls. The incidence rate of EPI was 1.18 cases per 1000 person-years and the median onset of EPI was 390 days after the first dose of ICI. All 23 (100%) EPI cases had steatorrhea that improved with pancrelipase, 12 (52.2%) had weight loss, and 9 (39.1%) had abdominal discomfort; none had changes of chronic pancreatitis on imaging. Nine (39%) EPI patients had episodes of clinical acute pancreatitis preceding the onset of EPI, compared to 1 (2%) control (OR 18.0 (2.5-789.0), P < .001). Finally, the EPI group exhibited higher proportions of new or worsening hyperglycemia after ICI exposure compared with the control group (9 (39.1%) vs. 3 (6.5%), P < .01). CONCLUSION: ICI-related EPI is a rare but clinically significant event that should be considered in patients with late onset diarrhea after ICI treatment and often is associated with development of hyperglycemia and diabetes.

Group sequential testing under instrumented difference-in-differences approach.

Unmeasured confounding is a major obstacle to reliable causal inference based on observational studies. Instrumented difference-in-differences (iDiD), a novel idea connecting instrumental variable and standard DiD, ameliorates the above issue by explicitly leveraging exogenous randomness in an exposure trend. In this article, we utilize the above idea of iDiD, and propose a novel group sequential testing method that provides valid inference even in the presence of unmeasured confounders. At each time point, we estimate the average or conditional average treatment effect under iDiD setting using the data accumulated up to that time point, and test the significance of the treatment effect. We derive the joint distribution of the test statistics under the null using the asymptotic properties of M-estimation, and the group sequential boundaries are obtained using the α $$ \alpha $$ -spending functions. The performance of our proposed approach is evaluated on both synthetic data and Clinformatics Data Mart Database (OptumInsight, Eden Prairie, MN) to examine the association between rofecoxib and acute myocardial infarction, and our method detects significant adverse effect of rofecoxib much earlier than the time when it was finally withdrawn from the market.

Preoperative glucose in surgical oncology patient is not associated with postoperative outcomes after adjustment for frailty.

BACKGROUND: Observational studies have shown associations between even small elevations in preoperative glucose and poorer outcomes, including increased length of stay (LOS) and higher mortality. This has led to calls for aggressive glycemic control in the preoperative period, including delay of treatment until glucose is reduced. However, it is not known whether there is a direct causal effect of blood glucose or whether adverse outcomes result from overall poorer health in patients with higher glucose. METHODS: Analysis was performed using a retrospective database of patients aged 65 and older who underwent cancer surgery. The last measured preoperative glucose was the exposure variable. The primary outcome was extended LOS (>4 days). Secondary outcomes included mortality, acute kidney injury (AKI), major postoperative complications during the admission period, and readmission within 30 days. The primary analysis was a logistic regression with prespecified covariates: age, sex, surgical service, and the Memorial Sloan Kettering-Frailty Index. In an exploratory analysis, lasso regression was used to select covariates from a list of 4160 candidate variables. RESULTS: This study included 3796 patients with a median preoperative glucose of 104 mg/dL (interquartile range: 93-125). Higher preoperative glucose was univariately associated with increased odds of LOS > 4 days (odds ratio [OR]: 1.45, 95% confidence interval [CI]: 1.22-1.73), with similar results for AKI, readmission, and mortality. Adjustment for confounders eliminated these associations for LOS (OR: 0.97 [95% CI: 0.80-1.18]) and attenuated all other glucose-outcome associations. Lasso regression gave comparable results to the primary analysis. Using the upper bound of the respective 95% confidence interval, we estimated that, at best, successful reduction of elevated preoperative glucose would reduce the risk of LOS > 4 days, 30-day major complication, and 30-day mortality by 4%, 0.5%, and 1.3%, respectively. CONCLUSIONS: Poor outcomes following cancer surgery in older adults with elevated glucose are most likely related to poorer overall health in these patients rather than a direct causal effect of glucose. Aggressive glycemic management in the preoperative period has very limited potential benefits and is therefore unwarranted.

Sodium-Glucose Cotransporter-2 Inhibitors for Hyperglycemia in Phosphoinositide 3-kinase Pathway Inhibition.

Purpose Phosphoinositide 3-kinase (PI3K) inhibition is used for the treatment of certain cancers, but can cause profound hyperglycemia and insulin resistance, for which sodium-glucose cotransporter-2 (SGLT2) inhibitors have been proposed as a preferred therapy. The objective of this research is to assess the effectiveness and safety of SGLT2 inhibitors for hyperglycemia in PI3K inhibition. Methods We conducted a single-center retrospective review of adults initiating the PI3k inhibitor alpelisib. Exposure to different antidiabetic drugs and adverse events including diabetic ketoacidosis (DKA) were assessed through chart review. Plasma and point-of-care blood glucoses were extracted from the electronic medical record. Change in serum glucose and the rate of DKA on SGLT2 inhibitor versus other antidiabetic drugs were examined as co-primary outcomes. Results We identified 103 patients meeting eligibility criteria with median follow-up of 85 days after starting alpelisib. When SGLT2 inhibitors were used to treat hyperglycemia, they were associated with a decrease in mean random glucose by -54 mg/dL (95% CI -99 to -8) in adjusted linear modeling. Five cases of DKA were identified, two occurring in patients on alpelisib plus SGLT2 inhibitor. Estimated incidence of DKA was: alpelisib plus SGLT2 inhibitor, 24 DKA cases per 100 patient-years (95% CI 6, 80); alpelisib with non-SGLT2 inhibitor antidiabetic drugs, 7 (95% CI 0.1, 34); alpelisib only, 4 (95% CI 0.1, 21). Conclusions SGLT2 inhibitors are effective treatments for hyperglycemia in the setting of PI3K inhibition, but given possible adverse events, SGLT2 inhibitors should be used with caution.

Rejoinder to "Instrumented difference-in-differences".

We thank all the discussants for the careful reading and insightful comments. In our rejoinder, we extend the discussion of how the assumptions of instrumented difference-in-differences (iDID) compare to the assumptions of the standard instrumental variable method. We also make additional comments on how iDID is related to the fuzzy DID. We highlight future research directions to enhance the utility of iDID, including extensions to adjust for covariate shift in two-sample iDID design, and generalization of iDID to multiple time points and a multi-valued instrumental variable for DID.

Prescriber Uncertainty as Opportunity to Improve Care of Type 2 Diabetes with Chronic Kidney Disease: Mixed Methods Study.

BACKGROUND: Over 5 million patients in the United States have type 2 diabetes mellitus (T2D) with chronic kidney disease (CKD); antidiabetic drug selection for this population is complex and has important implications for outcomes. OBJECTIVE: To better understand how providers choose antidiabetic drugs in T2D with CKD DESIGN: Mixed methods. Interviews with providers underwent qualitative analysis using grounded theory to identify themes related to antidiabetic drug prescribing. A provider survey used vignettes and direct questions to quantitatively assess prescribers' knowledge and preferences. A retrospective cohort analysis of real-world prescribing data assessed the external validity of the interview and survey findings. PARTICIPANTS: Primary care physicians, endocrinologists, nurse-practitioners, and physicians' assistants were eligible for interviews; primary care physicians and endocrinologists were eligible for the survey; prescribing data were derived from adult patients with serum creatinine data. MAIN MEASURES: Interviews were qualitative; for the survey and retrospective cohort, proportion of patients receiving metformin was the primary outcome. KEY RESULTS: Interviews with 9 providers identified a theme of uncertainty about guidelines for prescribing antidiabetic drugs in patients with T2D and CKD. The survey had 105 respondents: 74 primary care providers and 31 endocrinologists. Metformin was the most common choice for patients with T2D and CKD. Compared to primary care providers, endocrinologists were less likely to prescribe metformin at levels of kidney function at which it is contraindicated and more likely to correctly answer a question about metformin's contraindications (71% versus 41%) (p < .05). Real-world data were consistent with survey findings, and further showed low rates of use of sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists (<10%) in patients with eGFR below 60 ml/min/1.73m2. CONCLUSIONS: Providers are unsure how to treat T2D with CKD and incompletely informed as to existing guidelines. This suggests opportunities to improve care.

Instrumented difference-in-differences.

Unmeasured confounding is a key threat to reliable causal inference based on observational studies. Motivated from two powerful natural experiment devices, the instrumental variables and difference-in-differences, we propose a new method called instrumented difference-in-differences that explicitly leverages exogenous randomness in an exposure trend to estimate the average and conditional average treatment effect in the presence of unmeasured confounding. We develop the identification assumptions using the potential outcomes framework. We propose a Wald estimator and a class of multiply robust and efficient semiparametric estimators, with provable consistency and asymptotic normality. In addition, we extend the instrumented difference-in-differences to a two-sample design to facilitate investigations of delayed treatment effect and provide a measure of weak identification. We demonstrate our results in simulated and real datasets.

Impact of the Affordable Care Act's Physician Payments Sunshine Act on branded statin prescribing.

OBJECTIVE: To evaluate the impact of the Affordable Care Act's Physician Payments Sunshine Act (PPSA), which mandates disclosure of industry payments to physicians, on physician prescribing of branded statins. DATA SOURCES: Administrative claims data from 2011 to 2015 from three large national commercial insurers were provided by the Health Care Cost Institute. STUDY DESIGN: We adopted a difference-in-differences and event study design, leveraging the control group of physicians in two states, MA and VT, which implemented state laws on disclosure of industry payments prior to the national PPSA. To further address potential confounding caused by differences in prescribing patterns across states, our analytical sample includes physicians practicing in border counties between the treatment (NH, NY, and RI) and control (MA and VT) states. DATA COLLECTION: We restricted our sample to physicians who had at least 50 new-fill prescription claims for statins during the five-year study period, with at least one new-fill prescription claim each year. PRINCIPAL FINDINGS: We found that the PPSA led to a 7% (p < 0.001) reduction in monthly new prescriptions of brand-name statin over the study period, with little change in generic prescribing. The reduction in branded prescriptions was concentrated among physicians with the highest tercile of drug spending pre-PPSA, with a decrease of 15% (p < 0.001) in new branded statin prescriptions. The decline was most prominent after mandated reporting of industry payments began before the payment data was published. CONCLUSIONS: The PPSA may have achieved its intended effect of reducing branded prescriptions at least in the short run, particularly among physicians most likely to have engaged in excessive or low-value prescribing of branded drugs.

Baseline haemoglobin A1c and the risk of COVID-19 hospitalization among patients with diabetes in the INSIGHT Clinical Research Network.

AIMS: To examine the association between baseline glucose control and risk of COVID-19 hospitalization and in-hospital death among patients with diabetes. METHODS: We performed a retrospective cohort study of adult patients in the INSIGHT Clinical Research Network with a diabetes diagnosis and haemoglobin A1c (HbA1c) measurement in the year prior to an index date of March 15, 2020. Patients were divided into four exposure groups based on their most recent HbA1c measurement (in mmol/mol): 39-46 (5.7%-6.4%), 48-57 (6.5%-7.4%), 58-85 (7.5%-9.9%), and ≥86 (10%). Time to COVID-19 hospitalization was compared in the four groups in a propensity score-weighted Cox proportional hazards model adjusting for potential confounders. Patients were followed until June 15, 2020. In-hospital death was examined as a secondary outcome. RESULTS: Of 168,803 patients who met inclusion criteria; 50,016 patients had baseline HbA1c 39-46 (5.7%-6.4%); 54,729 had HbA1c 48-57 (6.5-7.4%); 47,640 had HbA1c 58-85 (7.5^%-9.9%) and 16,418 had HbA1c ≥86 (10%). Compared with patients with HbA1c 48-57 (6.5%-7.4%), the risk of hospitalization was incrementally greater for those with HbA1c 58-85 (7.5%-9.9%) (adjusted hazard ratio [aHR] 1.19, 95% confidence interval [CI] 1.06-1.34) and HbA1c ≥86 (10%) (aHR 1.40, 95% CI 1.19-1.64). The risk of COVID-19 in-hospital death was increased only in patients with HbA1c 58-85 (7.5%-9.9%) (aHR 1.29, 95% CI 1.06, 1.61). CONCLUSIONS: Diabetes patients with high baseline HbA1c had a greater risk of COVID-19 hospitalization, although association between HbA1c and in-hospital death was less consistent. Preventive efforts for COVID-19 should be focused on diabetes patients with poor glucose control.

Comparative Safety of Sodium-Glucose Cotransporter 2 Inhibitors Versus Dipeptidyl Peptidase 4 Inhibitors and Sulfonylureas on the Risk of Diabetic Ketoacidosis.

OBJECTIVE: To assess the association of sodium-glucose cotransporter 2 (SGLT2) inhibitors with diabetic ketoacidosis compared with dipeptidyl peptidase 4 (DPP-4) inhibitors and sulfonylureas in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: We conducted a new-user active comparator cohort study to examine two pairwise comparisons: 1) SGLT2 inhibitors versus DPP-4 inhibitors and 2) SGLT2 inhibitors versus sulfonylureas. The main outcome was diabetic ketoacidosis present on hospital admission. We adjusted for confounders through propensity score matching. We used Cox proportional hazards regression with a robust variance estimator to estimate hazard ratios (HRs) and corresponding 95% CIs while adjusting for calendar time. RESULTS: In cohort 1 (n = 85,125 for SGLT2 inhibitors and n = 85,125 for DPP-4 inhibitors), the incidence rates of diabetic ketoacidosis per 1,000 person-years were 6.0 and 4.3 for SGLT2 inhibitors and DPP4 inhibitors, respectively. In cohort 2 (n = 72,436 for SGLT2 inhibitors and n = 72,436 for sulfonylureas), the incidence rates of diabetic ketoacidosis per 1,000 person-years were 6.3 and 4.5 for SGLT2 inhibitors and sulfonylureas, respectively. In Cox proportional hazards regression models, the use of SGLT2 inhibitors was associated with a higher rate of diabetic ketoacidosis compared with DPP-4 inhibitors (adjusted HR [aHR] 1.63; 95% CI 1.36, 1.96) and sulfonylureas (aHR 1.56; 95% CI 1.30, 1.87). CONCLUSIONS: In this comparative safety study using real-world data, patients with type 2 diabetes who were newly prescribed SGLT2 inhibitors had a higher rate of diabetic ketoacidosis compared with DPP-4 inhibitors and sulfonylureas. Clinicians should be vigilant about this association.

Characterization, management, and risk factors of hyperglycemia during PI3K or AKT inhibitor treatment.

PURPOSE: The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway controls insulin sensitivity and glucose metabolism. Hyperglycemia is one of the most common on-target adverse effects (AEs) of PI3K/AKT inhibitors. As several PI3K and AKT inhibitors are approved by the United States Food and Drug Administration or are being studied in clinical trials, characterizing this AE and developing a management strategy is essential. METHODS: Patients with hematologic or solid malignancies treated at Memorial Sloan Kettering Cancer Center with a PI3K or AKT inhibitor were included in this retrospective analysis. A search for patients experiencing hyperglycemia was performed. The frequency, management interventions and outcomes were characterized. RESULTS: Four hundred and ninety-one patients with 10 unique cancer types who received a PI3K or AKT inhibitor were included. Twelve percent of patients required a dose interruption, 6% of patients required a dose reduction and 2% of patients were hospitalized to manage hyperglycemia. No events occurred among patients receiving ß-, γ-, or δ- specific PI3K inhibitor. There was one case where the PI3K or AKT inhibitor was permanently discontinued due to hyperglycemia. Metformin was the most commonly used antidiabetic medication, followed by insulin, sodium-glucose transport protein 2 (SGLT2) inhibitors, and sulfonylurea. SGLT2 inhibitors were associated with the greatest reductions in blood sugar, followed by metformin. At least one case of euglycemic diabetic ketoacidosis (DKA) occurred in a patient on PI3K inhibitor and SGLT2 inhibitor. Body mass index ≥ 25 and HbA1c  ≥ 5.7 are were independently significant predictors of developing hyperglycemia. CONCLUSION: Hyperglycemia is one of the major on-target side effects of PI3K and AKT inhibitors. It is manageable with antidiabetic medications, treatment interruption and/or dose modification. We summarize pharmacological interventions that may be considered for PI3K/AKT inhibitor induced hyperglycemia. SGLT2-inhibitor may be a particularly effective second-line option after metformin but there is a low risk of euglycemic DKA, which can be deadly. To our knowledge, our report is the largest study of hyperglycemia in patients receiving PI3K/AKT inhibitors.

Impact of a Provider Tele-mentoring Learning Model on the Care of Medicaid-enrolled Patients With Diabetes.

BACKGROUND: Project ECHO (Extension for Community Healthcare Outcomes), a tele-mentoring program for health care providers, has been shown to improve provider-reported outcomes, but there is insufficient research on patient-level outcomes. OBJECTIVES: To evaluate the impact of primary care provider (PCP) participation in Project ECHO on the care of Medicaid enrollees with diabetes. RESEARCH DESIGN: New Jersey Medicaid claims and encounter data and difference-in-differences models were used to compare utilization and spending between Medicaid patients seen by PCPs participating in a Project ECHO program to those of matched nonparticipating PCPs. SUBJECTS: A total of 1776 adult Medicaid beneficiaries (318 with diabetes), attributed to 25 participating PCPs; and 9126 total (1454 diabetic) beneficiaries attributed to 119 nonparticipating PCPs. MEASURES: Utilization and spending for total inpatient, diabetes-related inpatient, emergency department, primary care, and endocrinologist services; utilization of hemoglobin A1c tests, eye exams, and diabetes prescription medications among diabetics, and total Medicaid spending. RESULTS: Participation in Project ECHO was associated with decreases of 44.3% in inpatient admissions (P=0.001) and 61.9% in inpatient spending (P=0.021) among treatment relative to comparison patients. Signs of most other outcome estimates were consistent with hypothesized program effects but without statistical significance. Sensitivity analyses largely confirmed these findings. CONCLUSIONS: We find evidence that Project ECHO participation was associated with large and statistically significant reductions of inpatient hospitalization and spending. The study was observational and limited by a small sample of participating PCPs. This study demonstrates the feasibility and potential value of quasi-experimental evaluation of Project ECHO patient outcomes using claims data.

Chronic Medication Nonadherence and Potentially Preventable Healthcare Utilization and Spending Among Medicare Patients.

BACKGROUND: The association between nonadherence to chronic medications and potentially preventable healthcare utilization and spending is largely unknown. OBJECTIVES: To examine the associations of chronic medication nonadherence with potentially preventable utilization and spending among patients who were prescribed diabetic medications, renin-angiotensin system antagonists (RASA) for hypertension, or statins for high cholesterol, and compare the associations by patient race/ethnicity and socioeconomic status. DESIGN: Retrospective cohort study. Medicare fee-for-service claims data from 2013 to 2016 for 177,881 patients. MEASURES: Medication nonadherence was defined as having a below 80% proportion of days covered in each 6-month interval after the index prescription. Potentially preventable utilization was measured by preventable emergency department visits and preventable hospitalizations. Potentially preventable spending was calculated as the geographically adjusted spending associated with preventable encounters. RESULTS: After adjustment for other patient characteristics, medication nonadherence was associated with a 1.7-percentage-point increase (95% confidence interval [CI]: 1.4 to 2.0 percentage points, p < 0.001) in the probability of preventable utilization among the diabetic medication cohort, a 1.7-percentage-point increase (95% CI: 1.5 to 1.9 percentage points, p < 0.001) among the RASA cohort, and a 1.0-percentage-point increase (95% CI: 0.8 to 1.1 percentage points, p < 0.001) among the statin cohort. Among patients with at least one preventable encounter, medication nonadherence was associated with $679-$898 increased preventable spending. The incremental probability of preventable utilization and incremental spending associated with nonadherence were higher among racial/ethnic minority and low socioeconomic groups. CONCLUSIONS: Improving medication adherence is a potential avenue to reducing preventable utilization and spending. Interventions are needed to address racial/ethnic and socioeconomic disparities.

Angiotensin-Converting Enzyme Inhibitors Used Concomitantly with Insulin Secretagogues and the Risk of Serious Hypoglycemia.

Serious hypoglycemia is a major adverse event associated with insulin secretagogues. Previous studies have suggested a potential relationship between angiotensin-converting enzyme inhibitors (ACEIs) used with sulfonylureas and serious hypoglycemia, and widely used drug compendia warn of this potential drug-drug interaction. We investigated the association between serious hypoglycemia and concomitant use of ACEIs in patients receiving insulin secretagogues, using the self-controlled case series design and Medicaid claims data from 5 US states linked to Medicare claims from 1999-2011. The exposure of interest was active prescription for ACEIs during insulin secretagogue or metformin (negative control object drug) episodes. The outcome was hospital presentation for serious hypoglycemia, identified by discharge diagnosis codes in inpatient and emergency department claims (positive predictive value ~ 78-89%). We calculated confounder-adjusted rate ratios (RRs) and 95% confidence internals (CIs) of outcome occurrence during ACEI-exposed vs. ACEI-unexposed time using conditional Poisson regression. The RRs for ACEIs were not statistically elevated during observation time of glipizide (RR, 1.06; CI, 0.98-1.15), glyburide (RR, 1.05; CI, 0.96-1.15), repaglinide (RR, 1.15; CI, 0.94-1.41), or metformin (RR, 1.02; CI, 0.97-1.06); but was modestly elevated with glimepiride (RR, 1.23; CI, 1.11-1.37) and modestly reduced with nateglinide (RR, 0.73; CI, 0.56-0.96). The overall pattern of results do not suggest that ACEIs used with insulin secretagogues were associated with increased rates of serious hypoglycemia, with the possible exception of glimepiride.