Improved prediction of all-cause mortality by a combination of serum total testosterone and insulin-like growth factor I in adult men

OBJECTIVE

Lower levels of anabolic hormones in older age are well documented. Several studies suggested that low insulin-like growth factor I (IGF-I) or testosterone levels were related to increased mortality. The aim of the present study was to investigate the combined influence of low IGF-I and low testosterone on all-cause mortality in men.

METHODS AND RESULTS

From two German prospective cohort studies, the DETECT study and SHIP, 3942 men were available for analyses. During 21,838 person-years of follow-up, 8.4% (n=330) of men died. Cox model analyses with age as timescale and adjusted for potential confounders revealed that men with levels below the 10th percentile of at least one hormone [hazard ratio (HR) 1.38 (95% confidence-interval (CI) 1.06-1.78), p=0.02] and two hormones [HR 2.88 (95% CI 1.32-6.29), p<0.01] showed a higher risk of all-cause mortality compared to men with non-low hormones. The associations became non-significant by using the 20th percentile as cut-off showing that the specificity increased with lower cut-offs for decreased hormone levels. The inclusion of both IGF-I and total testosterone in a mortality prediction model with common risk factors resulted in a significant integrated discrimination improvement of 0.5% (95% CI 0.3-0.7%, p=0.03).

CONCLUSIONS

Our results prove that multiple anabolic deficiencies have a higher impact on mortality than a single anabolic deficiency and suggest that assessment of more than one anabolic hormone as a biomarker improve the prediction of all-cause mortality.

Circulating Troponin As Measured by a Sensitive Assay for Cardiovascular Risk Assessment in Primary Prevention

BACKGROUND

Measuring circulating cardiac troponin using novel sensitive assays has revealed that even minute elevations are associated with increased mortality in patients with coronary artery disease or even in the general population. Less well defined, however, is the incremental value of measuring circulating cardiac troponin I (cTnI) by a sensitive assay for risk assessment in primary prevention.

METHODS

We measured circulating concentrations of cTnI, N-terminal pro–B-type natriuretic peptide (NT-proBNP), and high-sensitivity C-reactive protein (hsCRP) in 5388 individuals free of known cardiovascular disease recruited into the DETECT study, a prospective longitudinal population-based cohort study. We determined the prognostic implications for incident major adverse cardiovascular events (MACE) during 5 years of follow-up.

RESULTS

Circulating cTnI was detectable in 19% of the subjects. Increased cTnI concentrations were associated with established risk factors for atherosclerosis and demonstrated a graded relationship with all-cause mortality and incident MACE during 5-year follow-up. A single measurement of cTnI significantly improved risk prediction over established risk factors, and also added prognostic information, when adjusted for serum concentrations of NT-proBNP and hsCRP.

CONCLUSIONS

Minute increases in cTnI are associated with increased mortality and incident MACE in a large primary prevention cohort and, thus, identify contributors to cardiovascular risk not fully captured by traditional risk factor assessment.

Type 2 diabetes mellitus and medications for type 2 diabetes mellitus are associated with risk for and mortality from cancer in a German primary care cohort

There is growing evidence that patients with type 2 diabetes mellitus have increased cancer risk. We examined the association between diabetes, cancer, and cancer-related mortality and hypothesized that insulin sensitizers lower cancer-related mortality. Participants in the Diabetes Cardiovascular Risk and Evaluation: Targets and Essential Data for Commitment of Treatment study, a nationwide cross-sectional and prospective epidemiological study, were recruited from German primary care practices. In the cross-sectional study, subjects with type 2 diabetes mellitus had a higher prevalence of malignancies (66/1308, 5.1%) compared to nondiabetic subjects (185/6211, 3.0%) (odds ratio, 1.64; 95% confidence interval, 1.12-2.41) before and after adjustment for age, sex, hemoglobin A(1c), smoking status, and body mass index. Patients on metformin had a lower prevalence of malignancies, comparable with that among nondiabetic patients, whereas those on any other oral combination treatment had a 2-fold higher risk for malignancies even after adjusting for possible confounders; inclusion of metformin in these regimens decreased the prevalence of malignancies. In the prospective analyses, diabetic patients in general and diabetic patients treated with insulin (either as monotherapy or in combination with other treatments) had a 2- and 4-fold, respectively, higher mortality rate than nondiabetic patients, even after adjustment for potential confounders (incidence of cancer deaths in patients with type 2 diabetes mellitus [2.6%] vs the incidence of cancer deaths in patients without type 2 diabetes mellitus [1.2%]). Our results suggest that diabetes and medications for diabetes, with the exception of the insulin sensitizer metformin, increase cancer risk and mortality.

The DETECT adherence score--structure and psychometric exploration of a novel approach to measure adherence to drug and non-drug interventions in primary care

There is substantial evidence that patient compliance or rather adherence to medical measures and recommendations for lifestyle changes can pivotally influence the prognosis of the patients or disease progression. However, the scientific evaluation and the statistical analysis of "patient adherence" are extremely difficult due to the fact that the construct of "adherence" is complex and comprised of many layers, and varies greatly in different disease groups. With this paper, we describe the development and structure of this novel assessment tool that takes past and prospective information on different facets of drug and behavioural adherence into account, expected to result in considerably improved prediction of future cardiovascular risk. We suggest a simple scoring scheme and explore the psychometric properties and the higher order factorial structure. In this exploratory study the "Diabetes Cardiovascular Risk Evaluation Targets and Essential Data for Commitment of Treatment" (DETECT) adherence score revealed good psychometric properties in terms of internal consistency and factorial structure, suggesting that its further exploration in terms of external validity is promising. Findings also underline that it is useful and informative to cover within one score both, pharmacologic and non-pharmacologic interventions in primary care. Our combination in this respect is unique, as most studies conducted on this subject so far aimed at assessing solely drug adherence or behavioural adherence.

All-cause mortality and serum insulin-like growth factor I in primary care patients

OBJECTIVE

Previous population-based studies provided conflicting results regarding the association of total serum insulin-like growth factor I (IGF-I) and mortality. The aim of the present study was to assess the relation of IGF-I levels with all-cause mortality in a prospective study.

DESIGN

DETECT (Diabetes Cardiovascular Risk-Evaluation: Targets and Essential Data for Commitment of Treatment) is a large, multistage, and nationally representative study of primary care patients in Germany. The study population included 2463 men and 3603 women. Death rates were recorded by the respective primary care physician. Serum total IGF-I levels were determined by chemiluminescence immunoassays and categorized into three groups (low, moderate, and high) according to the sex- and age-specific 10th and 90th percentiles.

RESULTS

Adjusted analyses revealed that men with low [hazard ratio (HR) 1.70 (95% confidence interval [CI] 1.05-2.73), p=0.03] and high [HR 1.76 (95% CI 1.09-2.85), p=0.02] IGF-I levels had higher risk of all-cause mortality compared to men with moderate IGF-I levels. The specificity of low IGF-I and high IGF-I levels increased with lower and higher cut-offs, respectively. No such association became apparent in women.

CONCLUSIONS

The present study revealed a U-shaped relation between IGF-I and all-cause mortality in male primary care patients.

Resting heart rate as a tool for risk stratification in primary care: does it provide incremental prognostic information?

BACKGROUND

Several selected population-based studies have emphasized the significance of resting heart rate as an independent cardiovascular risk factor. However, there are no data available for using resting heart rate as a cardiovascular risk predictor in contemporary primary care. Thus, the aim of our analysis was to examine the clinical value of the measurement of resting heart rate in a large, unselected population-based cohort of primary care subjects under the conditions of contemporary primary prevention.

DESIGN

Prospective, population-based cohort study.

METHODS

We examined a subgroup of 5320 unselected primary care subjects free of coronary artery disease from the nationwide, longitudinal Diabetes Cardiovascular Risk Evaluation Targets and Essential Data for Commitment of Treatment (DETECT) cohort study, which was conducted from 2003 to 2008.

RESULTS

During the follow-up time of 5 years, 258 events were reported. Elevated resting heart rate was not associated with an increased risk for cardiovascular events (HR = 0.75, p = 0.394), cardiovascular mortality (HR = 0.71, p = 0.616) or major cardiovascular events (HR = 0.77, p = 0.376). By cross-sectional analysis, elevated heart rate clustered with markers of the metabolic syndrome, like increased blood pressure (systolic: OR = 5.54, p < 0.0001; diastolic: OR = 3.82, p < 0.0001), elevated fasting plasma glucose levels (OR = 8.84, p < 0.0001), hypertriglyceridaemia (OR = 22.16, p = 0.001), and obesity (body mass index OR = 0.89, p < 0.0001). Assessment of resting heart rate in clinical practice had minimal and non-significant additional prognostic value compared to established cardiovascular risk factors as judged by C statistics (C = 0.001, p = 0.979).

CONCLUSION

The measurement of resting heart rate in the daily routine of primary care does not provide incremental prognostic information for cardiovascular risk stratification.

Prediction of incident diabetes mellitus by baseline IGF1 levels

OBJECTIVE

IGF1 is associated with metabolic parameters and involved in glucose metabolism. Low-IGF1 has been implicated in the etiology of glucose intolerance and subjects with pathological causes of either low- or high-IGF1 are at risk of diabetes. We hypothesized that both low- and high-IGF1 levels increase the risk of diabetes and aimed to assess the role of IGF1 in the risk of developing diabetes in a large prospective study.

DESIGN

An analysis of two prospective cohort studies, the DETECT study and SHIP.

METHODS

We measured IGF1 levels in 7777 nondiabetic subjects and assessed incident diabetes mellitus during follow-up.

RESULTS

There were 464 cases of incident diabetes during 32 229 person-years (time of follow-up in the DETECT study and SHIP: 4.5 and 5 years respectively). There was no heterogeneity between both studies (P > 0.4). The hazard ratios (HRs) of incident diabetes in subjects with IGF1 levels below the 10th or above the 90th age- and sex-specific percentile, compared to subjects with intermediate IGF1 levels, were 1.44 (95% confidence interval (CI) 1.07-1.94) and 1.55 (95% CI 1.06-2.06) respectively, after multiple adjustment. After further adjustment for metabolic parameters, the HR for low-IGF1 became insignificant. Analysis of IGF1 quintiles revealed a U-shaped association of IGF1 with risk of diabetes. Results remained similar after exclusion of patients with onset of new diabetes within 1 year or with borderline glucose or HbA1c levels at baseline.

CONCLUSIONS

Subjects with low- or high-IGF1 level are at increased risk of developing diabetes.

Health-related quality of life in patients with a history of myocardial infarction and stroke

BACKGROUND

There is a lack of the generic data comparing the influence of different diseases on health-related quality of life (HrQoL) in a representative sample of primary care patients.

METHODS

Patient data were collected in the DETECT (Diabetes Cardiovascular Risk Evaluation: Targets and Essential Data for Commitment of Treatment) study including 55,000 patients.

RESULTS

3,109 patients (33.3% female) with myocardial infarction (MI), stroke or both were compared to patients with a wide range of other diagnoses. Stroke and MI patients revealed a lower HrQoL as compared to patients with other diagnoses. Stroke was associated with strongest quality of life reduction. Multivariate analysis revealed several different determining factors.

CONCLUSIONS

The reduction of HrQoL of patients with MI and stroke is primarily determined by the CNS insult. These data provide further evidence that early diagnosis and treatment of cardiovascular risk factors is essential to reduce subsequent stroke.

Low testosterone levels predict all-cause mortality and cardiovascular events in women: a prospective cohort study in German primary care patients

OBJECTIVE

Although associations between testosterone and cardiovascular (CV) morbidity in women have been proposed, no large prospective study has evaluated potential associations between testosterone and mortality in women. The objective was to determine whether baseline testosterone levels in women are associated with future overall or CV morbidity and mortality.

DESIGN

Prospective cohort study with a 4.5-year follow-up period.

METHODS

From a representative sample of German primary care practices, 2914 female patients between 18 and 75 years were analyzed for the main outcome measures: CV risk factors, CV diseases, and all-cause mortality.

RESULTS

At baseline, the study population was aged 57.96±14.37 years with a mean body mass index of 26.71±5.17 kg/m(2). No predictive value of total testosterone for incident CV risk factors or CV diseases was observed in logistic regressions. Patients with total testosterone levels in the lowest quintile Q1, however, had a higher risk to die of any cause or to develop a CV event within the follow-up period compared to patients in the collapsed quintiles Q2-Q5 in crude and adjusted Cox regression models (all-cause mortality: Q2-Q5 versus Q1: crude hazard ratios (HR) 0.49, 95% confidence interval (CI) 0.33-0.74; adjusted HR 0.62, 95% CI 0.42-0.939; CV events: Q2-Q5 versus Q1: crude HR 0.54, 95% CI 0.38-0.77; adjusted HR 0.68, 95% CI 0.48-0.97). Kaplan-Meier curves revealed similar data.

CONCLUSIONS

Low baseline testosterone in women is associated with increased all-cause mortality and incident CV events independent of traditional risk factors.

Adverse anthropometric risk profile in biochemically controlled acromegalic patients: comparison with an age- and gender-matched primary care population

GH and IGF-1 play an important role in the regulation of metabolism and body composition. In patients with uncontrolled acromegaly, cardiovascular morbidity and mortality are increased but are supposed to be normalised after biochemical control is achieved. We aimed at comparing body composition and the cardiovascular risk profile in patients with controlled acromegaly and controls. A cross-sectional study. We evaluated anthropometric parameters (height, weight, body mass index (BMI), waist and hip circumference, waist to height ratio) and, additionally, cardiovascular risk biomarkers (fasting plasma glucose, HbA1c, triglycerides, total cholesterol, HDL, LDL, and lipoprotein (a), in 81 acromegalic patients (58% cured) compared to 320 age- and gender-matched controls (ratio 1:4), sampled from the primary care patient cohort DETECT. The whole group of 81 acromegalic patients presented with significantly higher anthropometric parameters, such as weight, BMI, waist and hip circumference, but with more favourable cardiovascular risk biomarkers, such as fasting plasma glucose, total cholesterol, triglycerides and HDL levels, in comparison to their respective controls. Biochemically controlled acromegalic patients again showed significantly higher measurements of obesity, mainly visceral adiposity, than age- and gender-matched control patients (BMI 29.5 +/- 5.9 vs. 27.3 +/- 5.8 kg/m(2); P = 0.020; waist circumference 100.9 +/- 16.8 vs. 94.8 +/- 15.5 cm; P = 0.031; hip circumference 110.7 +/- 9.9 vs. 105.0 +/- 11.7 cm; P = 0.001). No differences in the classical cardiovascular biomarkers were detected except for fasting plasma glucose and triglycerides. This effect could not be attributed to a higher prevalence of type 2 diabetes mellitus in the acromegalic patient group, since stratified analyses between the subgroup of patients with acromegaly and controls, both with type 2 diabetes mellitus, revealed that there were no significant differences in the anthropometric measurements. Biochemically cured acromegalic patients pertain an adverse anthropometric risk profile, mainly because of elevated adiposity measurements, such as BMI, waist and hip circumference, compared to an age- and gender-matched primary care population.

Diabetes in primary care: prospective associations between depression, nonadherence and glycemic control

BACKGROUND

Findings are inconsistent regarding the degree to which depression may exert a negative impact on glycemic control in patients with type 2 diabetes. We therefore aimed to examine the longitudinal relationship between depression, behavioral factors, and glycemic control.

METHODS

In a prospective component of a nationally representative sample, 866 patients with type 2 diabetes aged >or=18 years completed a standardized assessment including a laboratory screening, questionnaires, and diagnostic measures. Subsequent to baseline (t(0)), patients were tracked over a period of 12 months (t(1)). Depression was assessed according to DSM-IV and ICD-10 criteria. Glycemic control was determined by levels of glycosylated hemoglobin (HbA(1c)); a level of >or=7% was judged as unsatisfactory. Regression analyses were performed to analyze the prospective relationship between depression, medication adherence, diabetes-related health behavior, and HbA(1c).

RESULTS

Patients with depression at t(0) revealed increased rates of medication nonadherence (adjusted OR: 2.67; CI: 1.38-5.15) at t(1). Depression (adjusted regression coefficient: beta = 0.96; p = 0.001) and subthreshold depression (beta = 1.01; p < 0.001) at t(0) also predicted increased problems with diabetes-related health behavior at t(1). Adjusted ORs for poor glycemic control (HbA(1c) >or=7%) at t(1) were also increased for patients with baseline depression (2.01; CI: 1.10-3.69). However, problems with medication adherence as well as problems with diabetes-related health behavior at t(0) did not predict poor glycemic control at t(1).

CONCLUSIONS

In a prospective representative study of patients with type 2 diabetes, baseline depression predicted problems with medication adherence, problems with health-related behaviors, and unsatisfactory glycemic control at follow-up.

The predictive value of different measures of obesity for incident cardiovascular events and mortality

CONTEXT

To date, it is unclear which measure of obesity is the most appropriate for risk stratification.

OBJECTIVE

The aim of the study was to compare the associations of various measures of obesity with incident cardiovascular events and mortality.

DESIGN AND SETTING

We analyzed two German cohort studies, the DETECT study and SHIP, including primary care and general population.

PARTICIPANTS

A total of 6355 (mean follow-up, 3.3 yr) and 4297 (mean follow-up, 8.5 yr) individuals participated in DETECT and SHIP, respectively.

INTERVENTIONS

We measured body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), and waist-to-hip ratio (WHR) and assessed cardiovascular and all-cause mortality and the composite endpoint of incident stroke, myocardial infarction, or cardiovascular death.

RESULTS

In both studies, we found a positive association of the composite endpoint with WHtR but not with BMI. There was no heterogeneity among studies. The relative risks in the highest versus the lowest sex- and age-specific quartile of WHtR, WC, WHR, and BMI after adjustment for multiple confounders were as follows in the pooled data: cardiovascular mortality, 2.75 (95% confidence interval, 1.31-5.77), 1.74 (0.84-3.6), 1.71 (0.91-3.22), and 0.74 (0.35-1.57), respectively; all-cause mortality, 1.86 (1.25-2.76), 1.62 (1.22-2.38), 1.36 (0.93-1.69), and 0.77 (0.53-1.13), respectively; and composite endpoint, 2.16 (1.39-3.35), 1.59 (1.04-2.44), 1.49 (1.07-2.07), and 0.57 (0.37-0.89), respectively. Separate analyses of sex and age groups yielded comparable results. Receiver operating characteristics analysis yielded the highest areas under the curve for WHtR for predicting these endpoints.

CONCLUSIONS

WHtR represents the best predictor of cardiovascular risk and mortality, followed by WC and WHR. Our results discourage the use of the BMI.

A novel nonparametric approach for estimating cut-offs in continuous risk indicators with application to diabetes epidemiology

BACKGROUND

Epidemiological and clinical studies, often including anthropometric measures, have established obesity as a major risk factor for the development of type 2 diabetes. Appropriate cut-off values for anthropometric parameters are necessary for prediction or decision purposes. The cut-off corresponding to the Youden-Index is often applied in epidemiology and biomedical literature for dichotomizing a continuous risk indicator.

METHODS

Using data from a representative large multistage longitudinal epidemiological study in a primary care setting in Germany, this paper explores a novel approach for estimating optimal cut-offs of anthropomorphic parameters for predicting type 2 diabetes based on a discontinuity of a regression function in a nonparametric regression framework.

RESULTS

The resulting cut-off corresponded to values obtained by the Youden Index (maximum of the sum of sensitivity and specificity, minus one), often considered the optimal cut-off in epidemiological and biomedical research. The nonparametric regression based estimator was compared to results obtained by the established methods of the Receiver Operating Characteristic plot in various simulation scenarios and based on bias and root mean square error, yielded excellent finite sample properties.

CONCLUSION

It is thus recommended that this nonparametric regression approach be considered as valuable alternative when a continuous indicator has to be dichotomized at the Youden Index for prediction or decision purposes.

Proven germline mosaicism in a father of two children with CHARGE syndrome

CHARGE syndrome is an autosomal dominant malformation syndrome caused by mutations in the CHD7 gene. The majority of cases are sporadic and only few familial cases have been reported. In these families, mosaicism in one parent, as well as parent- to-child transmission of a CHD7 mutation, has been described. In some further cases, germline mosaicism has been suggested. Here, we report the first case in which germline mosaicism could be demonstrated in a father of two affected children with CHARGE syndrome. The truncating mutation c.7302dupA in exon 34 of the CHD7 gene was found in both affected children but was not detected in parental lymphocytes. However, in DNA extracted from the father's spermatozoa, the c.7302dupA mutation could be identified. Furthermore, mutation analysis of DNA isolated from 59 single spermatozoa revealed that the c.7302dupA mutation occurs in 16 spermatozoa, confirming germline mosaicism in the father of the affected children. This result has a high impact for genetic counselling of the family and for their recurrence risk in further pregnancies.