Overview of global real-world data sources for pediatric pharmacoepidemiologic research.

PURPOSE: Given limited information available on real-world data (RWD) sources with pediatric populations, this study describes features of globally available RWD sources for pediatric pharmacoepidemiologic research. METHODS: An online questionnaire about pediatric RWD sources and their attributes and capabilities was completed by members and affiliates of the International Society for Pharmacoepidemiology and representatives of nominated databases. All responses were verified by database representatives and summarized. RESULTS: Of 93 RWD sources identified, 55 unique pediatric RWD sources were verified, including data from Europe (47%), United States (38%), multiregion (7%), Asia-Pacific (5%), and South America (2%). Most databases had nationwide coverage (82%), contained electronic health/medical records (47%) and/or administrative claims data (42%) and were linkable to other databases (65%). Most (71%) had limited outside access (e.g., by approval or through local collaborators); only 10 (18%) databases were publicly available. Six databases (11%) reported having >20 million pediatric observations. Most (91%) included children of all ages (birth until 18th birthday) and contained outpatient medication data (93%), while half (49%) contained inpatient medication data. Many databases captured vaccine information for children (71%), and one-third had regularly updated data on pediatric height (31%) and weight (33%). Other pediatric data attributes captured include diagnoses and comorbidities (89%), lab results (58%), vital signs (55%), devices (55%), imaging results (42%), narrative patient histories (35%), and genetic/biomarker data (22%). CONCLUSIONS: This study provides an overview with key details about diverse databases that allow researchers to identify fit-for-purpose RWD sources suitable for pediatric pharmacoepidemiologic research.

Contemporary Approaches Toward Neuromodulation of Fear Extinction and Its Underlying Neural Circuits.

Neuroscience and neuroimaging research have now identified brain nodes that are involved in the acquisition, storage, and expression of conditioned fear and its extinction. These brain regions include the ventromedial prefrontal cortex (vmPFC), dorsal anterior cingulate cortex (dACC), amygdala, insular cortex, and hippocampus. Psychiatric neuroimaging research shows that functional dysregulation of these brain regions might contribute to the etiology and symptomatology of various psychopathologies, including anxiety disorders and post traumatic stress disorder (PTSD) (Barad et al. Biol Psychiatry 60:322-328, 2006; Greco and Liberzon Neuropsychopharmacology 41:320-334, 2015; Milad et al. Biol Psychiatry 62:1191-1194, 2007a, Biol Psychiatry 62:446-454, b; Maren and Quirk Nat Rev Neurosci 5:844-852, 2004; Milad and Quirk Annu Rev Psychol 63:129, 2012; Phelps et al. Neuron 43:897-905, 2004; Shin and Liberzon Neuropsychopharmacology 35:169-191, 2009). Combined, these findings indicate that targeting the activation of these nodes and modulating their functional interactions might offer an opportunity to further our understanding of how fear and threat responses are formed and regulated in the human brain, which could lead to enhancing the efficacy of current treatments or creating novel treatments for PTSD and other psychiatric disorders (Marin et al. Depress Anxiety 31:269-278, 2014; Milad et al. Behav Res Ther 62:17-23, 2014). Device-based neuromodulation techniques provide a promising means for directly changing or regulating activity in the fear extinction network by targeting functionally connected brain regions via stimulation patterns (Raij et al. Biol Psychiatry 84:129-137, 2018; Markovic et al. Front Hum Neurosci 15:138, 2021). In the past ten years, notable advancements in the precision, safety, comfort, accessibility, and control of administration have been made to the established device-based neuromodulation techniques to improve their efficacy. In this chapter we discuss ten years of progress surrounding device-based neuromodulation techniques-Electroconvulsive Therapy (ECT), Transcranial Magnetic Stimulation (TMS), Magnetic Seizure Therapy (MST), Transcranial Focused Ultrasound (TUS), Deep Brain Stimulation (DBS), Vagus Nerve Stimulation (VNS), and Transcranial Electrical Stimulation (tES)-as research and clinical tools for enhancing fear extinction and treating PTSD symptoms. Additionally, we consider the emerging research, current limitations, and possible future directions for these techniques.

Antimicrobial drug use and the risk of glioma: A case-control study.

BACKGROUND: The use of antibiotics has been associated with increased risks of various cancers. Comprehensive information on the association of antibiotic use with the risk of glioma is lacking. METHODS: We performed a large case-control study based on the Clinical Practice Research Datalink (CPRD) GOLD from the United Kingdom. We identified 4423 glioma cases recorded between 1995 and 2020 and matched them to controls (1:10) on the date of diagnosis (i.e., the index date), age, sex, general practice, and number of years of medical history in the database prior to the index date. We conducted conditional logistic regression analyses to calculate odds ratios (ORs) with 95% confidence intervals (CIs). The exposures of interest were the use of antimicrobial drugs, including antibacterial, antiviral, antifungal, antiprotozoal, and anthelmintic drugs with specific subclasses, where possible. RESULTS: We found no substantially increased risk of glioma after ever-use of antibiotics (OR 1.13, 95% CI 1.03-1.24). The risk did not increase with the increasing number of prescriptions received or with increasing time from first use to cancer diagnosis. The use of polyenes was associated with a weakly decreased risk of glioma (OR 0.81, 95% CI 0.67-0.96).

Population structure and forensic genetic analyses in Guarani and Kaingang Amerindian populations from Brazil.

When DNA profile comparisons between a crime scene trace and a reference sample generate correspondence, the match probability has to be estimated, so that evaluation of the strength of the forensic DNA evidence can be made. The random match probability estimations require information on allele frequencies and an adjustment factor, referred to as theta (θ) or Fst, a co-ancestry correction factor for subpopulation effects. The θ value has been standardized for urban and isolated populations, but inconsistencies have been reported when it is specifically calculated for smaller and isolated populations, including Amerindian populations. Notably, attempts to characterize forensic markers of these minor populations have been extensively limited and more conservative estimates of the correction factor may be generated for each of them. Therefore, we estimate allele frequencies of 21 autosomal STR markers used for forensic testing and calculated relevant forensic parameters for the set. In addition, we featured the possible structure of five Brazilian Amerindian populations that have been genetically isolated for centuries so we could obtain the appropriate θ value for them. The sample consisted of 319 individuals: (1) 121 Kaingang, from two communities: Ivaí (KIV=61) and Rio das Cobras (KRC=60); and (2) 198 Guaranis from three communities: Mbya from Rio das Cobras (GRC=51), Guarani Ñandeva (GND=71) and Guarani Kaiowá (GKW=76). Between Guarani populations low (Rst=0.0402, p < 10-4) to high (Rst=0.1557, p < 10-5) differentiation was found. Regarding Guarani and Kaingang populations, intermediate (Rst=0.0590, p < 10-5) to high (Rst=0.1604, p < 10-5) differentiation was found. The two Kaingang populations showed very low differentiation between them (Rst=0.0017, p = 0.27), which justifies the union of both genetic data for forensic databases and calculations. The combined power of discrimination (PD) and the combined power of exclusion (PE) were calculated for each population, demonstrating the usefulness of this set of markers in forensic and kinship analysis regarding these populations. Considering the demographic heterogeneity of Amerindian populations in general, the Fst mean value (0.03) was evaluated regarding 43 different indigenous populations from the Americas, including Guaranis and Kaingangs. This result confirms the adequacy of the standardized θ value for the forensic random match probability estimations involving Amerindian populations.

Association between glycemic control and risk of venous thromboembolism in diabetic patients: a nested case-control study.

BACKGROUND: Previous studies suggested an elevated risk of venous thromboembolism (VTE) among patients with type 2 diabetes mellitus (T2DM), with a possible sex difference. The impact of glycemic control on the risk of VTE is unclear. Our objective was to analyze the association between glycemic control and the risk of unprovoked (idiopathic) VTE in men and women with T2DM. METHODS: We conducted a nested case-control analysis (1:4 matching) within a cohort of patients with incident T2DM between 1995 and 2019 using data from the CPRD GOLD. We excluded patients with known risk factors for VTE prior to onset of DM. Cases were T2DM patients with an unprovoked treated VTE. The exposure of interest was glycemic control measured as HbA1c levels. We conducted conditional logistic regression analyses adjusted for several confounders. RESULTS: We identified 2'653 VTE cases and 10'612 controls (53.1% females). We found no association between the HbA1c level and the risk of VTE in our analyses. However, when the most recent HbA1c value was recorded within 90 days before the index date, women with HbA1c levels > 7.0% had a 36-55% increased relative risk of VTE when compared to women with HbA1c > 6.5-7.0%. CONCLUSIONS: Our study raises the possibility that female T2DM patients with HbA1c levels > 7% may have a slightly higher risk for unprovoked VTE compared to women with HbA1c levels > 6.5-7.0%. This increase may not be causal and may reflect differences in life style or other characteristics. We observed no effect of glycemic control on the risk of VTE in men.

Antidiabetic Treatment, Level of Glycemic Control, and Risk of Fracture in Type 2 Diabetes: a Nested, Case-Control Study.

CONTEXT: Patients with type 2 diabetes mellitus (T2DM) have an increased risk of low-trauma fractures. However, the effect of antidiabetic medication in relation to glycemic control on the risk of fracture is poorly understood. OBJECTIVE: This work aimed to evaluate the association between the level of glycemic control, use of antidiabetic medication, and risk of low-trauma fractures in patients with newly diagnosed T2DM. METHODS: We conducted a nested case-control analysis among individuals registered in the Clinical Practice Research Datalink. The base population consisted of patients with newly diagnosed T2DM from 1995 to 2017. Cases were patients with a low-trauma fracture after T2DM diagnosis. We matched 4 controls to each case. Exposures of interest were glycemic control (last glycated hemoglobin [HbA1c] level before fracture) and type of diabetes treatment. We conducted conditional logistic regression analyses adjusted for several confounders. RESULTS: We identified 8809 cases and 35 219 controls. Patients with current metformin use and HbA1c levels of less than 7.0% and between 7.0-8.0% had a reduced risk of fractures (adjusted odds ratio 0.89; 95% CI, 0.83-0.96 and 0.81; 95% CI, 0.73-0.90, respectively) compared with untreated patients. However, in patients receiving metformin plus 1 or 2 other antidiabetic drugs, or insulin (alone or in addition to other antidiabetic medication), the level of glycemic control was not associated with the risk of fracture compared with untreated patients. CONCLUSIONS: While patients with good or medium glycemic control receiving current metformin monotherapy had a lower risk of fracture compared with untreated patients, glycemic control in patients receiving treatment other than metformin was not associated with risk of fracture.

Use of selective serotonin reuptake inhibitors, other antidepressant medication, and risk of cataract: a case-control study based on Swiss claims data.

PURPOSE: Three previous studies reported controversial results regarding selective serotonin reuptake inhibitor (SSRI) exposure and cataract development. We therefore aimed to assess risk of cataract associated with previous exposure to SSRI using data from a large health insurance in Switzerland. METHODS: In a case-control study, we analyzed individuals insured by the Helsana Group, a large Swiss health insurance provider. We matched patients aged 40 years or older with cataract extraction (i.e., a proxy for a cataract diagnosis) in 2014 or 2015 to four control patients, on age, sex, date of cataract extraction, and area of residence. Exposure of interest was the number of SSRI claims prior to cataract extraction. We conducted conditional logistic regression analyses to calculate odds ratios (OR) with 95% confidence intervals (CI). We adjusted our analyses for the presence of hypertension, diabetes, glaucoma, systemic steroid use, and use of other antidepressant drugs. RESULTS: We identified 13,773 cataract cases and 51,625 matched controls. Compared with non-use, long-term use of SSRI (≥ 20 claims) was not associated with an altered risk of cataract (adjusted OR 0.93, 95% CI 0.84-1.04). The analysis of the individual drug substances also yielded no statistically significant association between drug exposure and the risk of cataract. CONCLUSIONS: According to our study, use of SSRI does not change the risk of cataract in the overall population.

Understanding the links between cardiovascular disease and Parkinson's disease.

Studies investigating the associations between genetic or environmental factors and Parkinson's disease (PD) have uncovered a number of factors shared with cardiovascular disease, either as risk factors or manifestations of cardiovascular disease itself. Older age, male sex, and possibly type 2 diabetes are examples. On the other hand, coffee consumption and physical activity are each associated with a lower risk of both PD and cardiovascular disease. This observation raises questions about the underlying pathophysiological links between cardiovascular disease and PD. There is evidence for common mechanisms in the areas of glucose metabolism, cellular stress, lipid metabolism, and inflammation. On the other hand, smoking and total/low-density lipoprotein cholesterol appear to have opposite associations with cardiovascular disease and PD. Thus, it is uncertain whether the treatment of cardiovascular risk factors will impact on the onset or progression of PD. The available data suggest that a nuanced approach is necessary to manage risk factors such as cholesterol levels once the associations are better understood. Ultimately, the choice of therapy may be tailored to a patient's comorbidity profile. This review presents the epidemiological evidence for both concordant and discordant associations between cardiovascular disease and PD, discusses the cellular and metabolic processes that may underlie these links, and explores the implications this has for patient care and future research. © 2019 International Parkinson and Movement Disorder Society.

Autoimmune diseases and immunosuppressive therapy in relation to the risk of glioma.

Effectors from the immune system can modulate the course and possibly the early development of gliomas. We, therefore, hypothesized that autoimmune diseases associated with increased immune-surveillance may also modulate the risk of human glioma. To test this hypothesis, we used data from the well-validated Clinical Practice Research Datalink (CPRD) GOLD from the UK to analyze the association of immune-related disorders or use of immunosuppressive drugs and the risk of glioma. We identified 3112 incident glioma cases diagnosed between 1995 and 2017. We randomly selected up to 10 controls, matching them to glioma cases on age, sex, index date, general practice, and number of years of active history in the database prior to the index date. We performed conditional logistic regression analyses to estimate Odds Ratios (ORs) of glioma among those exposed to allergies, autoimmune diseases, and immunosuppressive drugs. Overall, we found no materially altered association between a history of any autoimmune disease (OR 0.98, 95% CI 0.86-1.11), allergy (OR 0.97, 95% CI 0.89-1.05), or use of immunosuppressive drugs and the risk of glioma. However, subgroup analyses among younger patients found a statistically significant increased risk of glioma in patients with a history of inflammatory bowel disease (IBD) (OR 2.59, 95% CI 1.31-5.12). There was also an inverse association between asthma and risk of glioma in patients with longer survival (OR 0.73, 95% CI 0.58-0.91) and between long-term duration diabetes and risk of glioma (OR 0.71, 95% CI 0.53-0.96).

ACE inhibitor use and risk of cataract: a case-control analysis.

BACKGROUND/AIM: Use of ACE inhibitors (ACEIs) has been associated with an increased risk of cataract in a previous observational study in humans. In contrast, ACEIs were associated with beneficial effects on cataract development in experimental studies. We assessed the risk of cataract in relation to exposure to ACEI and other antihypertensive drugs. METHODS: This is a case-control study based on data from the UK-based Clinical Practice Research Datalink (CPRD). We included first-time cataract patients aged ≥40 years between 1995 and 2015 and an equal number of cataract-free controls. We matched the controls to cases on age, sex, general practice, date of first cataract (ie, index date) and years of history in the CPRD prior to the index date. We assessed the number of prescriptions for ACEI and other antihypertensive drugs in detail and explored the use of single ACEI substances. We performed conditional logistic regression and conducted various sensitivity analyses to test the robustness of our findings. We calculated the risk of cataract associated with previous exposure to ACEI, measured as OR with 95% CIs, and adjusted the multivariable model for body mass index, smoking, diabetes, hypertension, prescriptions of systemic corticosteroids and other antihypertensive drugs. RESULTS: We identified 206 931 cataract cases and the same number of matched controls. Use of ACEI was not associated with a materially altered risk of cataract compared with non-use of ACEI, neither in the main analysis (OR 1.06, 95% CI 1.04 to 1.08) nor in any of the sensitivity or stratified analyses. CONCLUSION: In our large observational study, use of ACEI was not associated with an altered risk of cataract.

Association Between Glycemic Control and Risk of Fracture in Diabetic Patients: A Nested Case-Control Study.

CONTEXT: Diabetes mellitus (DM) has been associated with an increased risk of fractures. However, the effect of glycemic control on the risk of fracture is not well understood. OBJECTIVE: To evaluate the association between glycemic control and the risk of low-trauma fractures in patients with type 1 DM (T1DM) and type 2 DM (T2DM). DESIGN: Nested case-control analysis. SETTING: UK-based Clinical Practice Research Datalink. PATIENTS OR OTHER PARTICIPANTS: The study population was patients whose T1DM or T2DM had been newly diagnosed between 1995 and 2015. The cases were patients with a low-trauma fracture after DM onset. We matched four controls to each case by age, sex, general practice, fracture date, and DM type and duration. STATISTICAL ANALYSIS: Conditional logistic regression analyses were performed, adjusted for covariates, including body mass index, smoking, DM complications and medications. RESULTS: The study population included 3329 patients with T1DM and 44,275 patients with T2DM. The median duration between DM onset and fracture date was 4.5 years for both T1DM and T2DM. The risk of fracture was increased in the patients with T1DM with a mean hemoglobin A1c >8.0% (adjusted OR, 1.39; 95% CI, 1.06 to 1.83) compared with those patients with T1DM and a mean hemoglobin A1c ≤7.0%. No such effect was found in the patients with T2DM. Independently of glycemic control, the risk of fracture was elevated in patients with T2DM and the current use of rosiglitazone and pioglitazone. CONCLUSIONS: The effect of glycemic control on the risk of low-trauma fracture differs between patients with T1DM and T2DM. Poor glycemic control increased the risk of fractures in patients with T1DM but not in those with T2DM.

Cataract in patients with diabetes mellitus-incidence rates in the UK and risk factors.

AIMS: To analyze the risk of incident cataract (diagnosis or extraction) in patients with or without diabetes focusing on other comorbid conditions, antidiabetic drug use, and diabetes duration. METHODS: The study population comprised newly diagnosed diabetes patients (≥40 years) from the UK-based Clinical Practice Research Datalink (CPRD) between 2000 and 2015, and a random sample of the general population matched for age, sex, general practice, and year of diabetes diagnosis. We assessed cataract incidence rates (IRs) and performed a nested case-control analysis in the diabetic cohort to assess potential risk factors for a cataract. RESULTS: There were 56,510 diabetes patients included in the study. IRs of cataract were 20.4 (95% CI 19.8-20.9) per 1000 person-years (py) in patients with diabetes and 10.8 (95% CI 10.5-11.2) per 1000 py in the general population. IRs increased considerably around the age of 80 years and with a concomitant diagnosis of macular edema. The incidence rate ratio (IRR) was highest in patients of the age group of 45-54 years. In the nested case-control study, we identified 5800 patients with cataract. Risk of cataract increased with increasing diabetes duration (adj. OR 5.14, 95% CI 4.19-6.30 diabetes for ≥10 years vs. diabetes <2 years). CONCLUSIONS: According to our study, diabetes is associated with an approximately two-fold increased detection rate of cataract. The risk of cataract associated with diabetes is highest at younger ages. Patients with diabetic macular edema are at an increased risk for cataract as well as patients with long-standing diabetes.

Parkinson disease and the risk of epileptic seizures.

OBJECTIVE: To assess the association between incident Parkinson disease (PD) and subsequent incident epileptic seizures. METHODS: We conducted a retrospective cohort study with a nested case-control analysis using data from the U.K. Clinical Practice Research Datalink. We identified patients aged ≥40 years with an incident diagnosis of PD between 1995 and 2016 and a matched comparison group of PD-free individuals. We calculated crude incidence rates (IRs) with 95% confidence intervals (CIs) of epileptic seizures in PD patients and the PD-free comparison group, and corresponding crude incidence rate ratios (IRRs). In the nested case-control analysis, we calculated adjusted odds ratios (adj. ORs) of incident PD among cases with incident epileptic seizures and seizure-free controls overall and stratified by various seizure-provoking comorbidities. RESULTS: Among 23,086 incident PD patients and 92,343 PD-free individuals, we identified 898 patients with incident epileptic seizures. The crude IR of epileptic seizures in PD patients was 266.7/100,000 person-years (95% CI = 235.6-297.7), and in PD-free individuals it was 112.4/100,000 person-years (95% CI = 103.5-121.3; IRR = 2.37, 95% CI = 2.06-2.73). The adj. OR of epileptic seizures was 1.68 (95% CI = 1.43-1.98) in PD patients compared with PD-free individuals. PD patients with comorbid brain disorders (adj. OR = 12.36, 95% CI = 8.74-17.48) or with > 1 seizure-provoking comorbidity (adj. OR = 13.24, 95% CI = 10.15-17.25) were at the highest risk of epileptic seizures compared with PD-free individuals with no seizure-provoking comorbidities. INTERPRETATION: This study suggests that incident PD is associated with an increased risk of incident epileptic seizures. Ann Neurol 2018;83:363-374.

Diabetes, use of metformin, and the risk of meningioma.

BACKGROUND: Metformin is a commonly used oral antidiabetic agent that has been associated with decreased cancer risk. However, data regarding the association between metformin use and the risk of meningioma are unavailable. METHODS: We conducted a matched case-control analysis using data from the U.K.-based Clinical Practice Research Datalink (CPRD) to analyse diabetes status, duration of diabetes, glycemic control, and use of metformin, sulfonylureas, and insulin in relation to the risk of meningioma. We conducted conditional logistic regression analyses to determine relative risks, estimated as odds ratios (ORs) with 95% confidence intervals (CIs) and adjusted for body mass index, smoking, history of arterial hypertension, myocardial infarction, and use of estrogens (among women). RESULTS: We identified 2,027 meningioma cases and 20,269 controls. For diabetes there was the suggestion of an inverse association with meningioma (OR = 0.89; 95%CI = 0.74-1.07), which was driven by an inverse relation among women (OR = 0.78; 95%CI = 0.62-0.98), in whom we also noted a suggestive inverse association with duration of diabetes (p-value for trend = 0.071). For metformin there was a suggestive positive relation, particularly after matching on duration of diabetes and HbA1c level (OR = 1.64; 95%CI = 0.89-3.04). Sulfonylureas showed no clear association (OR = 0.91; 95%CI = 0.46-1.80). For insulin there was the suggestion of an inverse relation, in particular when comparing a high vs. low number of prescriptions (OR = 0.58; 95%CI = 0.18-1.83). CONCLUSION: Further studies are needed to solidify a possible inverse association between diabetes and meningioma risk and to clarify the role of antidiabetics in this context.

Selective Serotonin Reuptake Inhibitors and Cataract Risk: A Case-Control Analysis.

PURPOSE: Use of selective serotonin reuptake inhibitors (SSRIs) has been associated with an increased cataract risk. We aimed to assess cataract risk after exposure to SSRI or to other antidepressant drugs in a large electronic primary care database. DESIGN: Case-control study. PARTICIPANTS: The study population was derived from the UK-based Clinical Practice Research Datalink (CPRD). We included patients with first-time cataract aged ≥40 years between 1995 and 2015 and an equal number of cataract-free controls matched on age, sex, general practice, date of cataract recording (i.e., index date), and years of history in the CPRD before the index date. METHODS: We conducted conditional logistic regression analyses adjusted for body mass index, smoking, hypertension, diabetes, and systemic steroid use. Exposure of interest was the number of SSRI prescriptions and prescriptions for other antidepressant drugs. We further explored mutually exclusive use of single SSRI substances. In sensitivity analyses, we shifted the index date backwards by 2 years, and we restricted our analyses to cases and controls without a prior glaucoma diagnosis. MAIN OUTCOME MEASURES: Relative risk estimates as odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: We identified 206 931 cataract cases and the same number of matched controls. Current long-term use of SSRI (≥20 prescriptions) was not associated with an increased cataract risk (adjusted OR, 0.99; 95% CI, 0.94-1.03). However, in a subset of patients aged 40 to 64 years, we found a slightly increased risk of cataract for long-term SSRI users (adjusted OR, 1.24; 95% CI, 1.15-1.34) compared with nonusers. CONCLUSIONS: In these data, use of SSRI was not associated with an increased risk of cataract. The slightly increased OR for individuals younger than 65 years of age in association with long-term SSRI use needs to be investigated in further studies.

Metformin and the risk of renal cell carcinoma: a case-control analysis.

Metformin use has been associated previously with a decreased risk of cancer, but its association with renal cell carcinoma has not yet been investigated in observational studies. We aimed to explore the association between the use of metformin and other antidiabetic drugs and the risk of renal cell carcinoma (RCC). We carried out a case-control analysis in the UK-based Clinical Practice Research Datalink. We included individuals with an incident RCC between January 1995 and December 2013 younger than the age of 90 years. Six controls per case were matched on age, sex, calendar time, general practice, and number of years of active history in the Clinical Practice Research Datalink before the index date. We included BMI, smoking, alcohol consumption, hypertension, and diabetes mellitus as potential confounders in a multivariate model using conditional logistic regression to calculate odds ratios with 95% confidence intervals, and we carried out a sensitivity analysis restricted only to diabetic cases and controls. Long-term use of metformin was not associated with an altered relative risk of RCC (≥30 prescriptions, adjusted odds ratio 1.18, 95% confidence interval 0.88-1.58), nor was use of other antidiabetic drugs. Results in the sensitivity analysis including only diabetic cases and controls were largely the same. Use of metformin or other antidiabetic drugs was not associated with a materially altered risk of RCC. Further studies are warranted.