Metformin use and risk of myeloproliferative neoplasms: a Danish population-based case-control study.

ABSTRACT: Previous studies have suggested that metformin has beneficial effects beyond its glucose-lowering properties, particularly in terms of its potential as an antineoplastic and cancer-preventive agent. In this study, we aimed to investigate the association between metformin use and the risk of myeloproliferative neoplasms (MPN). We conducted a population-based case-control study using Danish registers. Cases with MPN diagnosed between 2010 and 2018 were identified, and metformin use before the MPN diagnosis was ascertained. We compared metformin use among cases with MPN and an age- and sex-matched control group from the Danish general population to estimate age- and sex-adjusted odds ratios (ORs) and fully adjusted ORs (aORs) for the association between metformin use and risk of MPN. The study population included 3816 cases and 19 080 controls. Overall, 7.0% of cases and 8.2% of controls were categorized as ever-users of metformin, resulting in an OR for MPN of 0.84 (95% confidence interval [CI], 0.73-0.96) and an aOR of 0.70 (95% CI, 0.61-0.81). Long-term metformin use (≥5 years) was more infrequent and comprised 1.1% of cases and 2.0% of controls, resulting in an OR of 0.57 (95% CI, 0.42-0.79) and an aOR of 0.45 (95% CI, 0.33-0.63). A dose-response relationship was observed when cumulative duration of treatment was analyzed, and this was consistent in stratified analyses of sex, age, and MPN subtypes. In conclusion, metformin use was associated with significantly lower odds of an MPN diagnosis, indicating its potential cancer-preventive effect. Given the retrospective design, causality cannot be inferred.

Use of statins and risk of myeloproliferative neoplasms: a Danish nationwide case-control study.

Previous studies have indicated a possible cancer-protective effect of statins in solid cancers; however, this has never been investigated in myeloproliferative neoplasms (MPNs). We aimed to investigate the association between statin use and the risk of MPNs in a nested nationwide case-control study, using Danish national population registries. Information on statin use was obtained from the Danish National Prescription Registry, and patients diagnosed with MPNs between 2010 and 2018 were identified from the Danish National Chronic Myeloid Neoplasia Registry. The association between statin use and MPNs was estimated using age- and sex-adjusted odds ratios (ORs) and fully adjusted ORs (aORs), adjusting for prespecified confounders. The study population included 3816 cases with MPNs and 19 080 population controls (5:1) matched for age and sex using incidence density sampling. Overall, 34.9% of the cases and 33.5% of the controls ever used statins, resulting in an OR for MPN of 1.07 (95% confidence interval [CI], 0.99-1.16) and an aOR of 0.87 (95% CI, 0.80-0.96), respectively. 17.2% were categorized as long-term users (≥5 years) among the cases compared with 19.0% among controls, yielding an OR for MPN of 0.90 (95% CI, 0.81-1.00) and an aOR of 0.72 (95% CI, 0.64-0.81). Analysis of the effect of the cumulative duration of statin use revealed a dose-dependent response, and the association was consistent for sex, age, and MPN subgroups and across different statin types. Statin users were associated with significantly lower odds of being diagnosed with an MPN, indicating a possible cancer-preventive effect of statins. The retrospective of this study precludes causal inferences.

The Danish Myelodysplastic Syndromes Database: Patient Characteristics and Validity of Data Records.

BACKGROUND: The Danish Myelodysplastic Syndromes Database (DMDSD) comprises nearly all patients diagnosed with myelodysplastic syndromes (MDS) in Denmark since 2010. The DMDSD has not yet been used for epidemiological research and the quality of registered variables remains to be investigated. OBJECTIVE: To describe characteristics of the patients registered in the DMDSD and to calculate predictive values and the proportion of missing values of registered data records. METHODS: We performed a nationwide cross-sectional validation study of recorded disease and treatment data on MDS patients during 2010-2019. Patient characteristics and the proportion of missing values were tabulated. A random sample of 12% was drawn to calculate predictive values with 95% confidence intervals (CIs) of 48 variables using information from medical records as a reference standard. RESULTS: Overall, 2284 patients were identified (median age: 76 years, men 62%). Of these, 10% had therapy-related MDS, and 6% had an antecedent hematological disease. Hemoglobin level was less than 6.2 mmol/L for 59% of patients. Within the first two years of treatment, 59% received transfusions, 35% received erythropoiesis-stimulating agents, and 15% were treated with a hypomethylating agent. For the majority of variables (around 80%), there were no missing data. A total of 260 medical records were available for validation. The positive predictive value of the MDS diagnosis was 92% (95% CI: 88-95). Predictive values ranged from 64% to 100% and exceeded 90% for 36 out of 48 variables. Stratification by year of diagnosis suggested that the positive predictive value of the MDS diagnosis improved from 88% before 2015 to 95% after. CONCLUSION: In this study, there was a high accuracy of recorded data and a low proportion of missing data. Thus, the DMDSD serves as a valuable data source for future epidemiological studies on MDS.

The impact of changed treatment patterns in multiple myeloma on health-care utilisation and costs, myeloma complications, and survival: A population-based comparison between two time periods in Denmark.

OBJECTIVES: To evaluate health-care utilisation and costs, myeloma complications and survival in Danish patients with multiple myeloma (MM) before and after implementation of new early-line treatments in 2009. METHODS: Based on data from the Danish National Health Registers, 3518 patients diagnosed with MM during 2002-2005 or 2010-2013 and randomly matched control individuals were identified, and health-care utilisation and costs were estimated. RESULTS: Health-care utilisation showed a marked shift from inpatient admissions towards outpatient visits. From early to late period, the mean annual number of outpatient visits increased by 22% and 28% in patients <65 years and ≥65 years, respectively. Additionally, the mean annual outpatient service costs increased correspondingly from 17 001€ to 23 643€ in younger patients and from 11 317€ to 16 144€ in the elderly. Increasing outpatient costs were outbalanced by lower inpatient admission costs and the adjusted total mean annual costs decreased in younger patients, probably partly due to fewer myeloma complications. The five-year survival rates increased markedly in both younger (HR = 0.51) and elderly (HR = 0.69) patients. CONCLUSION: Despite the introduction of new expensive early-line MM treatments in 2009, health-care costs remained stable due to a shift in health-care utilisation towards outpatient clinic care and fewer complications.