Building transparency and reproducibility into the practice of pharmacoepidemiology and outcomes research.

Real-world evidence (RWE) studies are increasingly used to inform policy and clinical decisions. However, there remain concerns about the credibility and reproducibility of RWE studies. Observational researchers should highlight the level of transparency of their studies by providing a succinct statement addressing study transparency with the publication of every paper, poster, or presentation that reports on a RWE study. In this paper, we propose a framework for an explicit transparency statement that declares the level of transparency a given RWE study has achieved across five key domains: 1) protocol, 2) pre-registration, 3) data, 4) code sharing, and 5) reporting checklists.

Risk of fractures and use of bisphosphonates in adult patients with immune thrombocytopenia-A nationwide population-based study.

Corticosteroids remain the first-line treatment of immune thrombocytopenia (ITP), but increase the risk of osteoporosis and fractures. Bisphosphonates are used for the treatment of osteoporosis, but their usage among patients with ITP has not been systemically described. We investigated the risk of fractures and the use of bisphosphonates in adult patients with primary (pITP) and secondary ITP (sITP) compared with matched comparators in a nationwide registry-based cohort study. We identified 4030 patients with pITP (median age 60 years [IQR, 40-74]), 550 with sITP (median age 59 years [IQR, 43-74]) and 182 939 age-sex-matched general population comparators. All individuals were followed for incident fractures. Bisphosphonate use was estimated for calendar-years and in temporal relation to the ITP diagnosis. Adjusted cause-specific hazard ratio (csHR) for any fracture was 1.37 (95% confidence interval [CI] 1.23; 1.54) for pITP and 1.54 (1.17; 2.03) for sITP. The first-year csHR was 1.82 (1.39; 2.40) for pITP and 2.78 (1.58; 4.91) for sITP. Bisphosphonate use over calendar-years and in the early years following ITP diagnosis was higher among patients with ITP diagnosis compared with the general population. In conclusion, the risk of fractures and the use of bisphosphonates are higher in patients with ITP compared with the general population.

Mental health and use of psychotropic prescription drugs in adult patients with primary immune thrombocytopenia: a nationwide population-based cohort study.

Patients with primary immune thrombocytopenia (ITP) suffer from reduced survival and quality of life, but the underlying reasons for this are largely undescribed. Mental health and the use of psychotropic drugs in ITP is unknown. We investigated the risk of hospital-registered mental health events including fatigue and the use of psychotropic drugs in adult patients with ITP compared with the general population, using nationwide registry-data. We identified 3,749 patients with ITP and 149,849 age- and sex-matched general population comparators in the Danish Health Registries in the period 1997-2016. The median age was 60 years (interquartile range [IQR], 40-73) and 53% were women. We followed the individuals for incident mental health events and estimated the use of psychotropic drugs over calendar-years and in temporal relation to diagnosis of ITP. The first year cumulative incidence of any mental health event was 2.3% (95% confidence interval [CI]: 1.9-2.9) in patients and 0.7% (95% CI: 0.6-0.7) in comparators, yielding an adjusted cause-specific hazard ratio (csHR) of 3.57 (95% CI: 2.84-4.50). The corresponding estimates for depression were 1.2% (95% CI: 0.9-1.6) and 0.3% (0.3-0.4) respectively, with an adjusted csHR of 3.53 (95% CI: 2.56-4.85). We found similar findings for anxiety and fatigue, but risks generally diminished after 1-5 years. The use of opioids, antidepressants, and benzodiazepines increased in temporal relation to diagnosis of ITP. The risk of mental health events and the use of psychotropic drugs is higher in adult patients with ITP compared with the general population, and has a temporal relation to diagnosis of ITP emphasizing that mental health in ITP is a concern.

Treatment trajectories for Danish individuals with type 2 diabetes in the era of emerging glucose-lowering therapies.

AIM: To analyse patterns of glucose-lowering therapies among people with type 2 diabetes (T2D) in Denmark from 2016 to 2023. MATERIALS AND METHODS: We examined time trends in the clinical profiles of people with T2D who initiated different glucose-lowering therapy classes for the first time. We furthermore investigated individual-level treatment trajectories following first-ever glucose-lowering therapy in people with or without cardiorenal disease. The study utilized data from the nationwide Danish health registries and included all individuals who filled a first-ever prescription for metformin, dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs), sodium-glucose co-transporter-2 inhibitors (SGLT-2is) or insulin, excluding those without HbA1c-confirmed T2D or probable type 1 diabetes. RESULTS: We included 260 393 individuals initiating a new glucose-lowering therapy class from 2016 to 2023, during which there were 6- and 3-fold increases in initiators of GLP-1RAs and SGLT-2is, respectively. The median HbA1c level at treatment initiation with GLP-1RAs or SGLT-2is decreased, from 67-68 mmol/mol in 2016-2017 to 57-58 mmol/mol in 2022-2023. Among individuals who initiated metformin as first-line therapy, the proportion who started additional glucose-lowering therapy within 2 years increased from 25% in 2016 to 40% in 2021. Among the 38% of individuals who had established cardiorenal disease when they initiated first-ever glucose-lowering therapy in 2020, 22% used SGLT-2is and 18% GLP-1RAs after 2.5 years, compared with 17% and 21% among initiators without cardiorenal disease, respectively. CONCLUSIONS: Our study documents a trend towards earlier T2D treatment intensification and an increase in the use of GLP-1RAs and SGLT-2is in Denmark. However, optimal T2D treatment is still not received by most individuals with early T2D and established cardiorenal disease.

Dicloxacillin is an inducer of intestinal P-glycoprotein but neither dicloxacillin nor flucloxacillin increases the risk of stroke/systemic embolism in direct oral anticoagulant users.

AIM: We aimed to assess if dicloxacillin/flucloxacillin reduces the therapeutic efficacy of direct oral anticoagulants (DOACs) and the underlying molecular mechanism. METHODS: In a randomized, crossover study, we assessed whether dicloxacillin reduces oral absorption of drugs through P-glycoprotein (P-gp) during 10 and 28 days of treatment. To study the impact of dicloxacillin/flucloxacillin on intestinal and hepatic expression of P-gp in vitro, we usd LS174T cells and 3D spheroids of primary human hepatocytes. Finally, we used nationwide Danish health registries and the UK's Clinical Practice Research Datalink to estimate hazard ratios (HRs) for the risk of stroke and systemic embolism following dicloxacillin/flucloxacillin exposure among DOAC users, using phenoxymethylpenicillin and amoxicillin as active comparators. RESULTS: Dicloxacillin reduced the area under the curve of dabigatran to a geometric mean ratio 10 days of 0.67 (95% confidence interval [CI]: 0.42-1.1) and geometric mean ratio 28 days of 0.72 (95% CI: 0.39-1.4), suggesting reduced oral absorption via increased P-gp expression. In vitro, dicloxacillin raised P-gp expression in both intestinal and liver cells, while flucloxacillin only affected liver cells. In the pharmacoepidemiologic study, dicloxacillin and flucloxacillin were not associated with increased risk of stroke/systemic embolism (dicloxacillin vs. phenoxymethylpenicillin HR: 0.93, 95% CI: 0.72-1.2; flucloxacillin vs. amoxicillin HR: 0.89, 95% CI: 0.51-1.5). CONCLUSIONS: Dicloxacillin increases expression of intestinal P-gp, leading to reduced oral absorption of dabigatran. However, concomitant use of dicloxacillin/flucloxacillin was not associated with stroke and systemic embolism among DOAC users, suggesting no clinical impact from the drug-drug interaction between dicloxacillin/flucloxacillin and DOACs.

Changes in the Use of Hydrochlorothiazide and Other Antihypertensive Drugs in Switzerland in Association With the Swissmedic Safety Alert Regarding Non-melanoma Skin Cancer: An Interrupted Time-Series Analysis Using Swiss Claims Data.

PURPOSE: Long-term use of hydrochlorothiazide increases the risk of non-melanoma skin cancer. We aimed to evaluate potential changes in the use of hydrochlorothiazide in Switzerland after a direct healthcare professional communication (DHPC) in November 2018 by Swissmedic. METHODS: We performed interrupted time-series analyses using a large Swiss healthcare claims database (2015-2021). Within monthly intervals, we quantified the total number of claims and the total dispensed 'defined daily doses' (DDD) for preparations containing (1) hydrochlorothiazide, (2) angiotensin-converting enzyme (ACE) inhibitors and angiotensin-II-receptor blockers (ARB), (3) calcium-channel blockers (CCB) and (4) thiazide-like diuretics per 10 000 persons. Using segmented linear regression, we quantified the pre-DHPC trend, the immediate change and the post-DHPC change in trend for total claims and DDD for the four drug classes weighted for the demographic distribution of the Swiss population. RESULTS: ACE inhibitors and ARB were the most frequently claimed antihypertensive drugs with 300-400 claims per 10 000 persons, which increased by 5.4% during the study period. The average number of hydrochlorothiazide claims (157/10 000 persons in 2015) declined by 35% between 2015 and 2021. The decrease started prior to the DHPC, but the DHPC was associated with an immediate 6.1% decline and an accelerated decline in claims over time after the DHPC (similar results for DDD). This coincided with a 23% increase in claims of CCB (dihydropyridine type) over 7 years, whereas use of other antihypertensives increased less. CONCLUSION: Our results suggest that the DHPC by Swissmedic in 2018 accelerated a pre-existing decline in the use of hydrochlorothiazide in Switzerland.

Exposure to Valsartan Products Containing Nitrosamine Impurities in the United States, Canada, and Denmark.

BACKGROUND: Following the mass recall of valsartan products with nitrosamine impurities in July 2018, the number of patients exposed to these products, the duration of exposure, and the potential for cancer remains unknown. Therefore, we assessed the extent and duration of use of valsartan products with a nitrosamine impurity in the United States, Canada, and Denmark. METHODS: We conducted a retrospective cohort study using administrative healthcare data from the US FDA Sentinel System, four Canadian provinces that contribute to the Canadian Network for Observational Drug Effect Studies (CNODES), and the Danish National Prescription Registry. Patients, 18 years and older between May 2012 and December 2020 with a valsartan dispensing were identified in each database. Patients were followed from the date of valsartan dispensing until discontinuation. We defined four valsartan exposure categories based on nitrosamine impurity status; recalled generic products with confirmed NDMA/NDEA levels (recalled-tested); recalled generic products that were not tested (recalled); non-recalled generic and non-recalled branded products. In Denmark, the recalled-tested category was not included due to absence of testing data. The proportion and duration of use of valsartan episodes stratified by nitrosamine-impurity status was calculated. RESULTS: We identified 3.3 and 2.8 million (United States) and 51.3 and 229 thousand (Canada) recalled-tested and recalled valsartan exposures. In Denmark, where valsartan exposure was generally low, there were 10 747 recalled exposures. Immediately after the recall notices were issued, there was increased rates of switching to a non-valsartan ARB. The mean duration of use of the recalled-tested products was 167 (±223.1) and 146 (±255.8) days in the United States and Canada respectively. For the recalled products, mean cumulative duration of use was 178 (±249.6), 269 (±397.3) and 166 (±251.0) days in the United States, Canada, and Denmark, respectively. CONCLUSION: In this cohort study, despite widespread use of recalled generic valsartan between 2012 and 2018, the duration of use was relatively short and probably did not pose an elevated risk of nitrosamine-induced cancer. However, since products with nitrosamine impurity could have been on the market over a 6-year period, patients exposed to these products for longer durations could have a potentially different risk of cancer.

Use of prescribed analgesics before and after exercise therapy and patient education in patients with knee or hip osteoarthritis.

The aim of this study was to investigate utilisation patterns of prescribed analgesics before, during, and after an exercise therapy and patient education program among patients with knee or hip osteoarthritis. This cohort study is based on data from the nationwide Good Life with osteoarthritis in Denmark (GLA:D®) patient-register linked with national health registries including data on prescribed analgesics. GLA:D® consists of 8-12 weeks of exercise and patient education. We included 35,549 knee/hip osteoarthritis patients starting the intervention between January 2013 and November 2018. Utilisation patterns the year before, 3 months during, and the year after the intervention were investigated using total dispensed defined daily doses (DDDs) per month per 1000 population as outcome. During the year before the intervention, use of prescribed paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), and opioids increased with 85%, 79% and 22%, respectively. During the intervention, use of paracetamol decreased with 16% with a stable use the following year. Use of NSAIDs and opioids decreased with 38% and 8%, respectively, throughout the intervention and the year after. Sensitivity analyses indicated that the prescription of most analgesics changed over time. For paracetamol, NSAIDs, and opioids, 10% of analgesic users accounted for 45%, 50%, and 70%, respectively, of the total DDDs dispensed during the study period. In general, analgesic use increased the year before the intervention followed by a decrease during the intervention and the year after. A small proportion of analgesic users accounted for half or more of all paracetamol, NSAIDs, and opioids dispensed during the study period.

Antiplatelet drugs and breast cancer risk in a large nationwide Danish case-control study.

Low-dose aspirin has been hypothesized to prevent cancer risk by inhibiting platelet aggregation. However, the anti-cancer effect of low-dose aspirin has recently been questioned and its effect on breast cancer development remains unclear. The impact of other antiplatelet drugs on breast cancer risk has rarely been evaluated. Thus, this study aimed to investigate the associations between breast cancer risk and antiplatelet drug use in a nationwide nested case-control study. From the Danish healthcare registries, we identified as cases all women with invasive breast cancer diagnosis between 2001 and 2018 (n = 68 852). The date of diagnosis corresponded to the index date. We matched cases to 10 population controls on age and calendar time, using risk set sampling. Controls were assigned the same index date as their matched case. We used the prescription registry to identify exposure to low-dose aspirin, clopidogrel and dipyridamole. We defined ever use of antiplatelet drugs as at least two prescriptions filled up to 1 year before the index date. We applied conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals for breast cancer associated with the use of antiplatelet drugs, overall, by breast cancer subtype and by cumulative dose. Twelve percent of women had ever been exposed to low-dose aspirin, 2% to clopidogrel and 2% to dipyridamole. In multivariable models, breast cancer risk was not associated with ever use of low-dose aspirin (OR = 1.00 [0.97-1.03]), clopidogrel (OR = 0.93 [0.87-1.00]), and dipyridamole (OR = 1.02 [0.94-1.10]), compared with never use, and there was no evidence of a dose-response relation. However, we found an inverse association between dipyridamole use and breast cancer risk among women aged <55 years old, with suggestion of a dose-response relationship (OR per 1000 Defined Daily Doses = 0.72 [0.54-0.95]). Associations did not differ by breast cancer histological type, estrogen receptor status or clinical stage at diagnosis. Overall, the findings from this study do not support the use of antiplatelet drugs for breast cancer prevention.

Use of methotrexate and risk of skin cancer: a nationwide case-control study.

BACKGROUND: Methotrexate (MTX) use has been suspected of increasing the risk of skin cancer. The aim of this investigation was to examine the association between the use of MTX and the risk of basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC) and cutaneous malignant melanoma (CMM). METHODS: In a nationwide Danish case-control study, we identified incident, histologically verified cases of BCC (n = 131,447), cSCC (n = 18,661) or CMM (26,068) from 2004 to 2018. We matched 10 controls to each case on sex and birth year using risk-set sampling and computed crude and adjusted odds ratios (ORs) using conditional logistic regression for the use of MTX (≥2.5 g) compared with never-use. RESULTS: Use of MTX was associated with increased risk of BCC, cSCC and CMM with adjusted ORs of (95% confidence interval) 1.29 (1.20-1.38), 1.61 (1.37-1.89) and 1.35 (1.13-1.61), respectively. For BCC and cSCC, ORs increased with higher cumulative doses. When restricting the study population to patients with psoriasis, the ORs were 1.43 (1.23-1.67), 1.18 (0.80-1.74) and 1.15 (0.77-1.72), respectively. CONCLUSIONS: We observed an increased risk of BCC and cSCC associated with the use of MTX with evidence of a dose-response pattern; however, the association was not consistent when restricting the study population to patients with psoriasis.