The Nordic prescription databases as a resource for pharmacoepidemiological research--a literature review

PURPOSE

All five Nordic countries have nationwide prescription databases covering all dispensed drugs, with potential for linkage to outcomes. The aim of this review is to present an overview of therapeutic areas studied and methods applied in pharmacoepidemiologic studies using data from these databases.

METHODS

The study consists of a Medline-based structured literature review of scientific papers published during 2005-2010 using data from the prescription databases in Denmark, Finland, Iceland, Norway, and Sweden, covering 25 million inhabitants. Relevant studies were analyzed in terms of pharmacological group, study population, outcomes examined, type of study (drug utilization vs. effect of drug therapy), country of origin, and extent of cross-national collaboration.

RESULTS

A total of 515 studies were identified. Of these, 262 were conducted in Denmark, 97 in Finland, 4 in Iceland, 87 in Norway, and 61 in Sweden. Four studies used data from more than one Nordic country. The most commonly studied drugs were those acting on the nervous system, followed by cardiovascular drugs and gastrointestinal/endocrine drugs. A total of 228 studies examined drug utilization and 263 focused on the effects and safety of drug therapy. Pregnant women were the most commonly studied population in safety studies, whereas prescribers' adherence to guidelines was the most frequent topic of drug utilization studies.

CONCLUSIONS

The Nordic prescription databases, with their possibility of record-linkage, represent an outstanding resource for assessing the beneficial and adverse effects of drug use in large populations, under routine care conditions, and with the potential for long-term follow-up.

Similar reference intervals for total testosterone in healthy young and elderly men: results from the Odense Androgen Study

CONTEXT

Ageing in men is associated with changes in levels of sex hormones.

OBJECTIVE

To evaluate differences in sex hormones in young and elderly men and the significance of comorbidity and fat mass on sex hormones in elderly men.

DESIGN

Cross-sectional.

PATIENTS

Seven hundred and eighty-three men aged 20-29 years and 600 men aged 60-74 years randomly recruited from the background population.

MEASUREMENTS

Sex hormones and sex hormone-binding globulin (SHBG) were measured, and reference intervals were determined in healthy individuals in both groups and in elderly men stratified according to whether they were obese or lean (waist circumference ≥102 cm).

RESULTS

Sex hormones were lower and SHBG higher in elderly men compared with the young cohort. Lower cut-offs for total testosterone (TT) in healthy, young and elderly men were similar [Lower cut-off (95% CI): Young: 11·7 (11·2-12·1) vs elderly: 11·2 (10·3-12·1) nmol/l], but lower and higher cut-offs of bioavailable testosterone (BT) and free testosterone (FT) were higher in young men. Higher levels of androgens were found in healthy elderly men compared with those with a chronic disease or obesity. Androgens were inversely associated with central fat mass (CFM), whereas SHBG was inversely and directly associated with CFM and lower extremity fat mass, respectively, in both young and elderly men.

CONCLUSION

Reference intervals for TT were comparable in healthy young and elderly men, but reference intervals for FT and BT were lower in elderly men due to higher levels of SHBG. Androgens and SHBG were lower in elderly men with chronic disease and inversely associated with CFM.

Polymorphisms of muscle genes are associated with bone mass and incident osteoporotic fractures in Caucasians

The interaction between muscle and bone is complex. The aim of this study was to investigate if variations in the muscle genes myostatin (MSTN), its receptor (ACVR2B), myogenin (MYOG), and myoD1 (MYOD1) were associated with fracture risk, bone mineral density (BMD), bone mineral content (BMC), and lean body mass. We analyzed two independent cohorts: the Danish Osteoporosis Prevention Study (DOPS), comprising 2,016 perimenopausal women treated with hormone therapy or not and followed for 10 years, and the Odense Androgen Study (OAS), a cross-sectional, population-based study on 783 men aged 20-29 years. Nine tag SNPs in the four genes were investigated. In the DOPS, individuals homozygous for the variant allele of the MSTN SNP rs7570532 had an increased risk of any osteoporotic fracture, with an HR of 1.82 (95 % CI 1.15-2.90, p = 0.01), and of nonvertebral osteoporotic fracture, with an HR of 2.02 (95 % CI 1.20-3.41, p = 0.01). The same allele was associated with increased bone loss (BMC) at the total hip of 4.1 versus 0.5 % in individuals either heterozygous or homozygous for the common allele (p = 0.006), a reduced 10-year growth in bone area at the total hip of 0.4 versus 2.2 and 2.3 % in individuals heterozygous or homozygous for the common allele, respectively (p = 0.01), and a nonsignificantly increased 10-year loss of total-hip BMD of 4.4 versus 2.7 and 2.9 % in individuals heterozygous or homozygous for the common allele, respectively (p = 0.08). This study is the first to demonstrate an association between a variant in MSTN and fracture risk and bone loss. Further studies are needed to confirm the findings.

Osteoprotegerin levels decrease during testosterone therapy in aging men and are associated with changed distribution of regional fat

The cardiovascular effects of testosterone treatment are debated. Osteoprotegerin (OPG) is an independent marker of cardiovascular risk. We investigated the effect of testosterone therapy on OPG levels in aging men with low normal bioavailable testosterone levels. A randomized, double-blinded, placebo-controlled study of 6 months testosterone therapy (gel) in 38 men aged 60-78 years with bioavailable testosterone <7.3 nmol/l and waist circumference >94 cm was performed. Clinical evaluation, OPG, and C-reactive protein (CRP) measurements were carried out. Lean body mass (LBM), total fat mass, and bone mineral density (BMD) were established by dual X-ray absorptiometry. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured by magnetic resonance imaging. Power calculation was based on an increase in LBM during testosterone therapy and responders were defined as testosterone treated patients with increased LBM (Δ LBM positive), n=14. Data are presented as median (interquartile range). Testosterone therapy decreased total fat mass and SAT, whereas VAT was unchanged (n=38). OPG levels decreased during testosterone therapy (from 2.0 (1.9-2.5) to 1.9 (1.6-2.2) ng/ml, p<0.05 vs. placebo), whereas CRP levels were unchanged (n=38). In responders to testosterone therapy (n=14), ΔOPG levels were inversely associated with ΔSAT (r= - 0.60, p=0.03) and positively associated with ΔVAT (r=0.56, p=0.04). OPG levels decreased during testosterone therapy suggesting decreased cardiovascular risk. Decreased OPG levels were associated with changes in regional fat distribution and future studies are needed to further evaluate the association between OPG and regional fat mass distribution.

What are the toxicological effects of mercury in Arctic biota?

This review critically evaluates the available mercury (Hg) data in Arctic marine biota and the Inuit population against toxicity threshold values. In particular marine top predators exhibit concentrations of mercury in their tissues and organs that are believed to exceed thresholds for biological effects. Species whose concentrations exceed threshold values include the polar bears (Ursus maritimus), beluga whale (Delphinapterus leucas), pilot whale (Globicephala melas), hooded seal (Cystophora cristata), a few seabird species, and landlocked Arctic char (Salvelinus alpinus). Toothed whales appear to be one of the most vulnerable groups, with high concentrations of mercury recorded in brain tissue with associated signs of neurochemical effects. Evidence of increasing concentrations in mercury in some biota in Arctic Canada and Greenland is therefore a concern with respect to ecosystem health.

Changes in GABAergic inputs in the paraventricular nucleus maintain sympathetic vasomotor tone in chronic heart failure

The paraventricular nucleus (PVN) of the hypothalamus is an important region of the brain involved in the regulation of sympathetic vasomotor tone. Accumulating evidence supports the idea that a change in hypothalamic γ-aminobutyric acid (GABA)-ergic inhibitory and glutamatergic excitatory inputs contribute to the exacerbated sympathetic drive in chronic heart failure (HF). The purpose of this study was to determine whether a possible imbalance between glutamatergic and GABAergic inputs to the PVN contributes to increased sympathetic outflow in HF in two different sympathetic territories. Renal (RSNA) and splanchnic sympathetic nerve activity (SSNA), mean arterial blood pressure (MAP) and heart rate were recorded from urethane-anesthetized HF or sham rats. The NMDA-glutamate and GABA-A receptor densities within the PVN were quantified in HF and sham rats by autoradiography. Bilateral microinjection of kynurenic acid (4nmol) into the PVN decreased MAP and RSNA and SSNA in HF but not in sham rats. Furthermore, in response to GABA-A blockade in the PVN by bicuculline (400 pmol), hypertension and SSNA were reduced in HF compared to sham. The quantification of ionotropic NMDA receptors and GABA-A receptors in the PVN showed a significant reduction of GABA-A in HF rats; however, the NMDA density in the PVN did not differ between groups. Thus, this study provides evidence that the sympathoexcitation is maintained by an imbalance between GABAergic and glutamatergic inputs in the PVN in HF. The reduced GABAergic input results in relatively augmented glutamatergic actions in the PVN of HF rats.

Socio-economic status influences blood pressure control despite equal access to care

OBJECTIVE

Denmark has a health care system with free and equal access to care irrespective of age and socio-economic status (SES). We conducted a cross-sectional study to investigate a possible association between SES and blood pressure (BP) control of hypertensive patients treated in general practice.

METHODS

We enrolled 184 general practices and 5260 hypertensive patients. The general practitioners reported information about BP and diagnosis of diabetes. Information about education, income, antihypertensive drug treatment and other co-morbidity was retrieved from relevant registers from Statistics Denmark. The outcome measure was BP control defined as BP <140/90 mmHg in general and <130/80 mmHg in diabetics.

RESULTS

Patients <65 years and with an educational level of 10-12 years had increased odds ratio (OR) of BP control compared to patients with an educational level <10 years. Patients ≥65 years had increased OR of BP control if they were married/cohabiting as compared to being single, whereas education and income had no impact in this age group. Diabetics had significantly reduced odds of BP control irrespective of age, educational or income level.

CONCLUSIONS

Despite equal access to care for all patients, SES had significant impact on BP control in this survey. Diabetes and cardiovascular disease also had a substantial influence irrespective of age, educational and income level.

Age associated differences in prevalence of individual rotterdam criteria and metabolic risk factors during reproductive age in 446 caucasian women with polycystic ovary syndrome

Clinical manifestations and metabolic risk factors may differ according to age in patients with polycystic ovary syndrome (PCOS). Therefore, a retrospective trans-sectional study in academic tertiary-care medical center was designed. A cohort of 446 premenopausal, Caucasian women (age range 15-49 years) with PCOS were divided into 4 subgroups according to age: group 1 (15-19 years, n=42), group 2 (20-29 years, n=180), group 3 (30-39 years, n=187), group 4 (40-49 years, n=37) and underwent clinical evaluation (Ferriman-Gallwey score, BMI, waist, blood pressure), hormone analyses (sex hormones, fasting lipids, insulin, glucose), transvaginal ultrasound, oral glucose tolerance tests (OGTT) (n=234), and ACTH tests (n=201). BMI, waist, Ferriman-Gallwey score, blood pressure, and lipid profile were higher in older vs. younger age groups whereas androgen levels were lower. Measures of insulin resistance were unchanged between age groups, but glucose levels were significantly higher in older age groups. Rotterdam criteria: The prevalence of PCO and biochemical hyperandrogenism decreased in the oldest age group whereas clinical hyperandrogenism increased. Young patients are characterized by PCO and biochemical hyperandrogenism, whereas older patients are more obese with more severe hirsutism and more cardiovascular and metabolic risk factors.

Genetic studies in congenital anterior midline cervical cleft

Congenital anterior midline cervical cleft (CAMCC) is a rare anomaly, with less than 100 cases reported. The cause of CAMCC is unknown, but genetic factors must be considered as part of the etiology. Three cases of CAMCC are presented. This is the first genetic study of isolated CAMCC. Conventional cytogenetics, array-comparative genomic hybridization (CGH) and whole exome sequencing were performed, including a search of relevant syndromes in the Online Mendelian Inheritance in Man (OMIM) database. Array CGH indicated a loss of the PAPPA gene in one of the patients, while exome sequencing showed a mutation in SIX5 in another patient. Both aberrations were inherited from unaffected parents. These results most likely imply that the identified mutations are not disease-causing, although they may be contributing factors if CAMCC has a polygenic inheritance.

Positive associations between serum levels of IGF-I and subcutaneous fat depots in young men. The Odense Androgen Study

INTRODUCTION

Serum levels of IGF-I are of growing interest due to the associations with morbidity and mortality. Despite markedly suppressed GH secretion, total IGF-I levels are often within normal range in obese adults.

AIM

To study associations between IGF-I and estimated muscle mass in the Odense Androgen Study population and secondly to investigate associations between serum IGF-I and regional fat depots.

METHOD

The Odense Androgen Study is a population-based, cross-sectional study of 776 randomly selected men aged 20-29 years. Regional lean and fat mass were measured by dual-energy X-ray absorptiometry, whereas regional muscle and fat areas were assessed by magnetic resonance imaging.

RESULTS

Age-adjusted IGF-I levels correlated significantly with different estimates of muscle mass (r-values between 0.15 and 0.19; p<0.001). Using multiple linear regression, serum IGF-I correlated positively with subcutaneous adipose tissue on the abdomen (SAT) after controlling for visceral adipose tissue (VAT) in the whole group and in the subgroup of men with normal waist circumference (r-values between 0.13 and 0.15; p<0.03). In addition, IGF-I correlated positively with subcutaneous thigh fat area (TFA) after controlling for intramyocellular lipid (imcl) r=0.18; p<0.004) and IGF-I correlated negatively with TFAimcl in the whole group and in the subgroup of men with normal waist circumference.

CONCLUSION

SAT and subcutaneous TFAs were positively associated with IGF-I in regression analyses. Conversely, imcl of the thigh was inversely associated with IGF-I levels. These findings emphasize the differential associations between IGF-I and regional fat deposits. Future studies may provide further insight regarding the interplay between circulating IGF-I levels and regional muscle and fat mass.

Prescribing indicators: what can Canada learn from European countries?

BACKGROUND

Drug therapy can improve patients' quality of life and health outcomes; however, underuse, overuse and inappropriate use of drugs can occur. Systematic examination of potential opportunities for improving prescribing and medication use is needed.

OBJECTIVE

To convene a diverse group of stakeholders to learn about and discuss advantages and limitations of data sources, tools and methods related to drug prescribing indicators; foster methods to assess safe, appropriate and cost-effective prescribing; increase awareness of international organizations who develop and apply performance indicators relevant to Canadian researchers, practitioners and decision-makers; and provide opportunities to apply information to the Canadian context.

METHODS

Approximately 50 stakeholders (health system decision-makers, senior and junior researchers, healthcare professionals, graduate students) met June 1-2, 2009 in Halifax, Canada. Four foundational presentations on evaluating quality of prescribing were followed by discussion in pre-assigned breakout groups of a prepared case (either antibiotic use or prescribing for seniors), followed by feedback presentations.

RESULTS

Many European countries have procedures to develop indicators for prescribing and quality use of medicines. Indicators applied in diverse settings across the European Union use various mechanisms to improve quality, including financial incentives for prescribers.

CONCLUSION

Further Canadian approaches to develop a system of Canadian prescribing indicators would enable federal/provincial/territorial and international comparisons, identify practice variations and highlight potential areas for improvement in prescribing, drug use and health outcomes across Canada. A more standardized system would facilitate cross-national research opportunities and enable Canada to examine how European countries use prescribing indicators, both within their country and across the European Union.

Testosterone therapy decreases subcutaneous fat and adiponectin in aging men

OBJECTIVE

Testosterone therapy increases lean body mass and decreases total fat mass in aging men with low normal testosterone levels. The major challenge is, however, to determine whether the metabolic consequences of testosterone therapy are overall positive. We have previously reported that 6-month testosterone therapy did not improve insulin sensitivity. We investigated the effect of testosterone therapy on regional body fat distribution and on the levels of the insulin-sensitizing adipokine, adiponectin, in aging men with low normal bioavailable testosterone levels.

DESIGN

A randomized, double-blinded, placebo-controlled study on 6-month testosterone treatment (gel) in 38 men, aged 60-78 years, with bioavailable testosterone <7.3 nmol/l, and a waist circumference >94 cm.

METHODS

Central fat mass (CFM) and lower extremity fat mass (LEFM) were measured by dual X-ray absorptiometry. Subcutaneous abdominal adipose tissue (SAT), visceral adipose tissue (VAT), and thigh subcutaneous fat area (TFA) were measured by magnetic resonance imaging. Adiponectin levels were measured using an in-house immunofluorometric assay. Coefficients (b) represent the placebo-controlled mean effect of intervention.

RESULTS

LEFM was decreased (b = -0.47 kg, P = 0.07) while CFM did not change significantly (b = -0.66 kg, P = 0.10) during testosterone therapy. SAT (b = -3.0%, P = 0.018) and TFA (b = -3.0%, P < 0.001) decreased, while VAT (b = 1.0%, P = 0.54) remained unchanged. Adiponectin levels decreased during testosterone therapy (b = -1.3 mg/l, P = 0.001).

CONCLUSION

Testosterone therapy decreased subcutaneous fat on the abdomen and lower extremities, but visceral fat was unchanged. Moreover, adiponectin levels were significantly decreased during testosterone therapy.

Treatment of 5413 hypertensive patients: a cross-sectional study

BACKGROUND

Most hypertensive patients are managed in primary care in Denmark, but previous studies have shown that only 21-43% of hypertensive patients achieve optimal blood pressure (BP) control. Antihypertensive drug treatment, risk factors and cardiovascular disease (CVD) are some of the important factors to consider when optimizing the individual treatment strategy in hypertensive patients.

OBJECTIVE

To examine treatment of BP according to Danish guidelines (BP < 140/90 mmHg generally and <130/80 mmHg for diabetics) in a population from general practice in relation to risk factors, CVD and diagnosis of diabetes.

METHODS

A cross-sectional study comprising 184 practices and 5413 hypertensive patients was carried out in Denmark. The general practitioners filled in information on each patient's risk factors, CVD and antihypertensive drug treatment. Patients filled in a questionnaire on risk factors. The outcome measures were optimal BP control according to Danish guidelines and antihypertensive drug treatment.

RESULTS

Mean patient age was 65.9 years [95% confidence interval (CI): 65.6-66.1]. Optimal BP control was achieved in 29.1% (95% CI: 27.9-30.3) of the study population. Among 842 diabetics with or without CVD, optimal BP control was achieved in 10.9% (95% CI: 8.8-10.3), while 38.7% (35.5-41.9) of patients with CVD achieved optimal BP control. The majority of all patients were treated with 1 (32.5%, 95% CI: 32.5 (31.3-33.8)) or two antihypertensive drugs (39.0%, 95% CI: 38.2-40.8). In hypertensive diabetics, 17.7% were not treated with an angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker.

CONCLUSION

In general practice, the proportion of hypertensive patients achieving optimal BP control is inadequate. The majority of hypertensive patients are treated with only one or two antihypertensive drugs.

[Clinical risk management in german hospitals - does size really matter?]

PURPOSE

In the last years, German hospitals have implemented different measures to increase patient safety. Special importance has been attached to near miss reporting systems (critical incident reporting system, CIRS) as instruments for risk identification in health care, instruments that promise high potential for organisational learning. To gain insight into the current status of critical incident reporting systems and other instruments for clinical risk management, a survey among 341 hospitals was carried out in 2009. Questions covered a process of six steps: from risk strategy to methods for risk identification, to risk analysis and risk assessment, to risk controlling and risk monitoring.

MATERIAL AND METHODS

Structured telephone interviews were conducted with 341 German hospitals, featuring in their statutory quality reports certain predefined key terms that indicated the concluded or planned implementation of clinical risk management. The main objective of those interviews was to check the relation between status/organisation of self-reported risk management and both operator (private, public, NPO) and size of hospital.

RESULTS

The implementation of near miss reporting systems (CIRS) in German hospitals has been constantly rising since 2004: in 2009, 54 % of the interviewed hospitals reported an implemented CIRS; of these, 72 % reported the system to be hospital-wide. An association between CIRS and private, public or NPO-operator could not be detected (Fisher p = 1.000); however, the degree of CIRS implementation was significantly increasing with the size of the hospital, i.e., the number of beds (Fisher p = 0.008): only 38 % of the hospitals with less than 100 beds reported CIRS implementation against 52 % of those between 100 to 500 beds, and 67 % of those with more than 500 beds. While 62 % of the hospitals interviewed reported the maintenance of a risk management committee, only 14 % reported the implementation of risk analysing techniques. As to clinical risk management, 92 % of the hospitals see potential for internal improvement; 44 % have already communicated with external consultants.

CONCLUSION

While identification of clinical risks with near miss and other incident reporting systems meets increasing acceptance, the learning potential based on incident reporting is not yet appropriately being used. There is a deficit regarding systematic and comprehensive risk assessment and controlling; this will have to be met by improving the organisational framework for clinical risk management.

Milk composition in free-ranging polar bears (Ursus maritimus) as a model for captive rearing milk formula

The goals of this study were to have an improved understanding of milk composition and to help create a suitable milk formula for cubs raised in captivity. Milk samples were evaluated for fat, fatty acids, carbohydrate, vitamin D(3), 25(OH)D(3), vitamin A (retinol), vitamin E (α-tocopherol), protein, and amino acids. Total lipids in milk did not differ for cubs (mean ± SEM = 26.60 ± 1.88 g/100 ml vs. yearlings 27.80 ± 2.20 g/100 ml). Milk lipids were of 23.6% saturated fatty acid for cubs and 22.4% for yearlings. Milk consumed by cubs and yearlings contained 43.8 and 42.0% mono-unsaturated fatty acids and 23.4 and 21.9% polyunsaturated fatty acids, respectively. Carbohydrate content was higher in milk for cubs (4.60 ± 0.64 g/100 ml) than for yearlings (2.60 ± 0.40 g/100 ml). Vitamin D(3) concentration of milk was 18.40 ± 5.00 ng/ml in early lactation compared with 7.60 ± 2.00 ng/ml for mid-lactation. 25(OH)D(3) was lower in milk consumed by cubs (162.00 ± 6.70 pg/ml) than in milk consumed by yearlings (205.00 ± 45.70 pg/ml). Vitamin A concentrations were 0.06 ± 0.01 and 0.03 ± 0.01 µg/ml for cubs and yearlings, respectively. Vitamin E was higher in milk consumed by cubs (20.16 ± 4.46 µg/ml) than by yearlings (7.30 ± 1.50 µg/ml). Protein content did not differ in milk available to cubs (11.40 ± 0.80 g/100 ml compared with milk for yearlings 11.80 ± 0.40 g/100 ml). Taurine was the most abundant free amino acid at 3,165.90 ± 192.90 nmol/ml (0.04% as fed basis).