Measurement of plasma total calcium before plasma free ionized calcium - a possibility with affordable pitfalls.

Free ionized calcium (fCa) is considered the gold standard for assessing calcium status in patients, but it is relatively expensive and is associated with several preanalytical and analytical error sources. We investigated the feasibility of using a reflex test that involves first measuring total calcium (tCa) and if out of reference range, then measure fCa, with expectation of reducing the number of fCa measurements. We used data from 1815 unique patients with concurrent measurement of fCa, tCa and albumin adjusted calcium (aCa). Patients were stratified by albumin level, and the association of fCa to tCa and aCa respectively was assessed with linear regression. The regression analysis showed the best linearity for tCa and aCa at albumin <35 g/L (R2: 0.80-0.90), and the poorest at albumin >40 g/L (R2: tCa 0.58; aCa 0.59). We examined the accuracy of hypo- and hypercalcemia classifications for tCa, aCa and the reflex test. aCa had more misclassifications of hypo- and hypercalcemia than tCa, with respectively 25% and 21%. Implementation of the reflex test would correct any false hypo- or hypercalcemia classified by tCa, leaving only false negative results corresponding to 9% of all tCa measurements. False negative results were on average 0.04 mmol/L above or below the reference range of fCa. Implementation of the reflex test reduces the number of fCa by 68% without major errors diagnosing hyper- or hypocalcemia.

Factors associated with statin discontinuation near end of life in a Danish primary health care cohort.

BACKGROUND: Long-term preventive treatment such as treatment with statins should be reassessed among patients approaching end of life. The aim of the study was to describe the rate of discontinuation of statin treatment and factors associated with discontinuation in the 6 months before death. METHODS: This study is a retrospective cohort study using national registers and blood test results from primary health care patients. Patients in the Copenhagen municipality, Denmark who died between 1997 and 2018 and were statin users during the 10-year period before death were included. We calculated the proportion who remained statin users in the 6-month period before death. Factors associated with discontinuation were tested using logistic regression. RESULTS: A total of 55,591 decedents were included. More patients continued treatment (64%, n = 35,693) than discontinued (36%, n = 19,898) the last 6 months of life. The 70 and 80 age groups had the lowest odds of discontinuing compared to the 90 (OR 1.59, 95% CI 0.93-2.72) and 100 (OR 3.11, 95% CI 2.79-3.47) age groups. Increasing comorbidity score (OR 0.89, 95% CI 0.87; 0.90 per 1-point increase) and use of statins for secondary prevention (OR 0.89, 95% CI 0.85; 0.93) reduced the likelihood of discontinuation as did a diagnosis of dementia, heart failure, or cancer. CONCLUSION: A substantial portion of patients continued statin treatment near end of life. Efforts to promote rational statin use and discontinuation are required among patients with limited life expectancy, including establishing clear, practical recommendations about statin discontinuation, and initiatives to translate recommendations into clinical practice.

Association of ferritin and transferrin saturation with all-cause mortality, and the effect of concurrent inflammation: a danish cohort study.

The association between ferritin and transferrin saturation (TS), respectively, and all-cause mortality is unclear. Furthermore, the influence of concurrent inflammation has not been sufficiently elucidated. We investigated these associations and the effect of concurrently elevated C-reactive protein (CRP), and accordingly report the levels associated with lowest all-cause mortality for females and males with and without inflammation.Blood test results from 161,921 individuals were included. Statistical analyses were performed in sex-stratified subpopulations, with ferritin or TS level as continuous exposure variables, and were adjusted for age, co-morbidity and inflammation status using CRP. An interaction was used to investigate whether the effect of ferritin or TS on all-cause mortality was modified by inflammation status (CRP ≥ 10 mg/L or CRP < 10 mg/L). Low and high ferritin and TS levels were respectively associated with increased all-cause mortality in females and in males. These associations persisted with concurrent CRP ≥ 10 mg/L. The ferritin level associated with lowest mortality was 60 µg/L for females and 125 µg/L for males with CRP < 10 mg/L. It was 52 µg/L for females and 118 µg/L for males with CRP ≥ 10 mg/L. The TS level associated with lowest mortality was 33.9% for females and 32.3% for males with CRP < 10 mg/L. It was 28.7% for females and 30.6% for males with CRP ≥ 10 mg/L.Our findings can nuance clinical interpretation and further aid in defining recommended ranges for ferritin and TS.

The 10 most frequently requested blood tests in the Capital Region of Denmark, 2010-2019 and simulated effect of minimal retesting intervals.

As healthcare costs continue to rise throughout the world, critical assessment of the appropriateness of expenses gain focus. OBJECTIVES: We aimed to describe the developments in test numbers of the 10 most frequently requested tests, and to simulate the effect of introducing minimal retesting intervals. DESIGN & METHODS: Data from the blood tests - albumin, alanine transaminase, cholesterol, creatinine, C-reactive protein, hemoglobin, hemoglobin A1c, potassium, sodium, and thyrotropin - from 2,687,589 patients handled by the Capital Region of Denmark from 2010 to 2019 was used. Tallies of each test per year were graphed. A simulation of the effect of minimal retesting intervals on test count and blood sampling volume was performed by virtually removing requests made prior to a set of possible minimal retesting intervals. RESULTS: Increases in requests were observed both from hospitals and general practitioners. The number of requests for hemoglobin A1c increased more than the other tests. The increases could not be accounted for by an increase in population size and aging of the population, and therefore suggests possible inappropriate increase in monitoring of patients. The simulated effect of applying minimal retesting intervals showed large reductions in tests and blood sampled. CONCLUSIONS: For hospitals, the simulation suggested that applying minimal retesting intervals could lead to significant reductions in both the number of blood tests performed and in the amount of blood drawn for testing. For general practitioners, the simulation showed only minimal reductions in number of tests and blood volume drawn.

Decreased plasma lipid levels in a statin-free Danish primary health care cohort between 2001 and 2018.

BACKGROUND: Lipid levels in blood have decreased considerably during the past decades in the general population partly due to use of statins. This study aims to investigate the trends in lipid levels between 2001 and 2018 in a statin-free population from primary health care, overall and by sex and age. METHODS: In a cohort of 634,119 patients from general practice with no diagnoses or medical treatments that affected lipid levels of total cholesterol (TC; n = 1,574,339) between 2001 and 2018 were identified. Similarly, measurements of low-density lipoprotein cholesterol (LDL-C; n = 1,302,440), high-density lipoprotein cholesterol (HDL-C; n = 1,417,857) and triglycerides (TG; n = 1,329,477) were identified. RESULTS: Mean TC decreased from 5.64 mmol/L (95% CI: 5.63-5.65) in 2001 to 5.17 mmol/L (95% CI: 5.16-5.17) in 2018 while LDL-C decreased from 3.67 mmol/L (95% CI: 3.66-3.68) to 3.04 mmol/L (95% CI: 3.03-3.04). Women aged 70-74 years experienced the largest decreases in TC levels corresponding to a decrease of 0.7 mmol/L. The decrease in LDL-C levels was most pronounced in men ≥85 years with a decrease of 0.9 mmol/L. For both genders, TC and LDL-C levels increased with advancing age until around age 50. After menopause the women had higher TC and LDL-C levels than the men. The median (geometric mean) TG level decreased by 0.4 mmol/L from 2001 to 2008, after which it increased slightly by 0.1 mmol/L until 2018. During life the TG levels of the men were markedly higher than the women's until around age 65-70. HDL-C levels showed no trend during the study period. CONCLUSIONS: The levels of TC and LDL-C decreased considerably in a statin-free population from primary health care from 2001 to 2018. These decreases were most pronounced in the elderly population and this trend is not decelerating. For TG, levels have started to increase, after an initial decrease.

Drug-drug interactions between vitamin K antagonists and statins: a systematic review.

PURPOSE: Concomitant use of vitamin K antagonists (VKA) and statins is frequent in cardiovascular patients. However, clinical guidelines on this drug combination are divergent. Therefore, we performed a systematic review to evaluate the effect of statin initiation on coagulation among VKA users. METHODS: Following the PRISMA guidelines, we applied two broad search strategies for the drug interaction between VKA and statins in both Embase and Pubmed; 8623 unique hits were obtained. In the final sample, eight studies were included. RESULTS: The most frequently used VKA in the studies was warfarin, while simvastatin was the most commonly initiated statin. All included studies showed a minor increase in the anticoagulant effect of VKA following statin initiation during VKA treatment. The reported increases in mean international normalized ratio (INR) ranged from 0.15-0.65. CONCLUSION: The anticoagulant effect of statin initiation in patients treated with VKA is likely to be of limited clinical relevance but should be evaluated individually.

Drug-drug interaction between warfarin and statins: A Danish cohort study.

Initiation of statin treatment is suggested to increase the international normalised ratio (INR) among warfarin users. However, available data is limited and conflicting. We conducted a register-based cohort study to evaluate the drug-drug interaction between warfarin and statins. By linking data on INR measurements and filled prescriptions, we identified warfarin users 2000-2015 initiating simvastatin (n = 1363), atorvastatin (n = 165) or rosuvastatin (n = 23). Simvastatin initiation led to an increase in mean INR from 2.40 to 2.71, with INRs peaking after 4 weeks, corresponding to a mean change of 0.32 (95%CI 0.25-0.38). High-dose and low-dose simvastatin led to comparable changes (mean change 0.33 vs 0.29). Initiation of atorvastatin and rosuvastatin lead to INR increases of 0.27 (95%CI 0.12-0.42) and 0.30 (95%CI -0.09-0.69). In conclusion, initiation of simvastatin, atorvastatin or rosuvastatin among warfarin users led to a minor increase in INR. The magnitude of this change is for most patients likely of limited clinical relevance.

Antimycotic Treatment of Oral Candidiasis in Warfarin Users.

PURPOSE: Azole antimycotics and nystatin oral solution are used to treat oral candidiasis. Azoles inhibit cytochrome (CYP) P450-dependent metabolism of warfarin, which could increase the anticoagulant effect of warfarin. Nystatin is not expected to interfere with warfarin metabolism, but current data are conflicting. With this study, we aimed to explore the potential drug-drug interactions between warfarin and azole antimycotics used in the treatment of oral candidiasis, that is, systemic fluconazole, miconazole oral gel, and nystatin oral solution. METHODS: By linking clinical data on international normalized ratio (INR) measurements with administrative data on filled prescriptions of warfarin and antimycotics during 2000-2015, we explored INR changes in warfarin users relative to initiation of systemic fluconazole (n = 413), miconazole oral gel (n = 330), and nystatin oral solution (n = 399). RESULTS: We found a significant increase in mean INR of 0.83 (95% confidence interval [CI] 0.61-1.04) and 1.27 (95% CI 0.94-1.59) following initiation of systemic fluconazole and miconazole oral gel, respectively. Also, the proportion of patients experiencing an INR-value above 5 was increased after initiation of fluconazole (from 4.3% to 15.3%) and miconazole (from 5.5% to 30.1%). INR was unaffected by initiation of nystatin oral solution (mean change 0.08; 95% CI -0.10 to 0.25). CONCLUSION: Initiation of systemic fluconazole and miconazole oral gel was associated with increased INR in warfarin users. A similar association was not found for nystatin oral solution, which thus appears to be the safest alternative when treating oral candidiasis in warfarin users.

A compulsory pop-up form reduces the number of vitamin D requests from general practitioners by 25 percent.

OBJECTIVE: Healthcare costs, including costs for laboratory tests, are increasing worldwide. One example is the measurement of vitamin D. General practitioners in the Capital Region of Denmark include a vitamin D status in approximately 20% of all laboratory requisitions. This study intended to examine the effect of a compulsory pop-up form in the electronic request system on the number of vitamin D tests and to monitor the indications. DESIGN: From 1 January 2017, we introduced a compulsory pop-up form in which the general practitioners had to state the indication for measuring vitamin D, choosing from a predefined set of indications. Intervention practitioners were compared with control practitioners before and after the intervention. SETTING: General practices in the Capital Region of Denmark. SUBJECTS: In total, 572 general practitioners and 383,964 patients were included in the period from 1 January 2016 to 31 December 2018. MAIN OUTCOME MEASURES: Number of vitamin D tests and distribution of indications. RESULTS: We observed a drop in number of vitamin D requisitions to 70% (in 2017) and 75% (in 2018) relative to 2016. During the same period, the number of requisitions increased by 33% in a non-intervention group of practitioners. The indication 'Monitoring of treatment with vitamin D' was the most frequently used indication, recorded in 121,475 patients. CONCLUSION: A compulsory pop-up form reduces the number of vitamin D requests from general practitioners by 25%. The implication is that pop-up forms can be used to decrease healthcare costs.

Change in HbA1c concentration as decision parameter for frequency of HbA1c measurement.

Hemoglobin A1c (HbA1c) is a long-term measure for glucose concentration in plasma. Since its introduction as a diabetes monitoring tool, and its more recent application as a diagnostic tool, the number of measurements of HbA1c have risen dramatically. However, HbA1c change is slow, so repeating measurements should not be done too often. We use a large, unfiltered dataset from 52,017 patients to determine the possible rate of change in HbA1c concentration. In our laboratory, the critical difference between HbA1c measurements is 8.5%. Our data show that a 1-unit HbA1c rise takes 4 weeks to occur, hence, at a HbA1c concentration around 50 mmol/mol Hgb, a critically increased HbA1c concentration cannot be determined until after 16 weeks. Conversely a critically lower HbA1c can manifest itself after 2 weeks, but after 7 weeks the dropping tendency stops. The amount of measurements that can be cancelled because they were taken sooner than 16 weeks is 23 percent.