Quantifying the improvement of surrogate indices of hepatic insulin resistance using complex measurement techniques

We evaluated the ability of simple and complex surrogate-indices to identify individuals from an overweight/obese cohort with hepatic insulin-resistance (HEP-IR). Five indices, one previously defined and four newly generated through step-wise linear regression, were created against a single-cohort sample of 77 extensively characterised participants with the metabolic syndrome (age 55.6±1.0 years, BMI 31.5±0.4 kg/m2; 30 males). HEP-IR was defined by measuring endogenous-glucose-production (EGP) with [6–62H2] glucose during fasting and euglycemic-hyperinsulinemic clamps and expressed as EGP*fasting plasma insulin. Complex measures were incorporated into the model, including various non-standard biomarkers and the measurement of body-fat distribution and liver-fat, to further improve the predictive capability of the index. Validation was performed against a data set of the same subjects after an isoenergetic dietary intervention (4 arms, diets varying in protein and fiber content versus control). All five indices produced comparable prediction of HEP-IR, explaining 39–56% of the variance, depending on regression variable combination. The validation of the regression equations showed little variation between the different proposed indices (r2 = 27–32%) on a matched dataset. New complex indices encompassing advanced measurement techniques offered an improved correlation (r = 0.75, P<0.001). However, when validated against the alternative dataset all indices performed comparably with the standard homeostasis model assessment for insulin resistance (HOMA-IR) (r = 0.54, P<0.001). Thus, simple estimates of HEP-IR performed comparable to more complex indices and could be an efficient and cost effective approach in large epidemiological investigations

Resistance training and testosterone levels in male patients with chronic kidney disease undergoing dialysis

Background. We investigated serum testosterone and insulin-like growth factor 1 (IGF-1) levels’ associations with muscle fibre size and resistance training in male dialysis patients. Methods. Male patients were included in a 16-week control period followed by 16 weeks of resistance training thrice weekly. Blood samples were obtained to analyse testosterone, luteinizing hormone (LH), IGF-1, and IGF-binding protein 3. Muscle fibres’ size was analysed in biopsies from m. vastus lateralis. Results. The patients’ testosterone levels were within the normal range at baseline (n=20) (19.5 (8.2–52.1) nmol/L versus 17.6 (16.1–18.0), resp.) whereas LH levels were higher (13.0 (5.5–82.8) U/L versus 4.3 (3.3–4.6), P<0.001, resp.). IGF-1 and IGF-binding protein 3 levels were higher in the patients compared with reference values (203 (59–590) ng/mL versus 151 (128–276), P=0.014, and 5045 (3370–9370) ng/mL versus 3244 (3020–3983), P<0.001, resp.). All hormone levels and muscle fibre size (n=12) remained stable throughout the study. Age-adjusted IGF-1 was associated with type 1 and 2 fibre sizes (P<0.05). Conclusion. Patients’ total testosterone values were normal due to markedly increased LH values, which suggest a compensated primary insufficiency of the testosterone producing Leydig cell. Even though testosterone values were normal, resistance training was not associated with muscle hypertrophy. This trial is registered with ISRCTN72099857

Resistance Training and Testosterone Levels in Male Patients with Chronic Kidney Disease Undergoing Dialysis

Background. We investigated serum testosterone and insulin-like growth factor 1 (IGF-1) levels' associations with muscle fibre size and resistance training in male dialysis patients. Methods. Male patients were included in a 16-week control period followed by 16 weeks of resistance training thrice weekly. Blood samples were obtained to analyse testosterone, luteinizing hormone (LH), IGF-1, and IGF-binding protein 3. Muscle fibres' size was analysed in biopsies from m. vastus lateralis. Results. The patients' testosterone levels were within the normal range at baseline (n = 20) (19.5 (8.2–52.1) nmol/L versus 17.6 (16.1–18.0), resp.) whereas LH levels were higher (13.0 (5.5–82.8) U/L versus 4.3 (3.3–4.6), P < 0.001, resp.). IGF-1 and IGF-binding protein 3 levels were higher in the patients compared with reference values (203 (59–590) ng/mL versus 151 (128–276), P = 0.014, and 5045 (3370–9370) ng/mL versus 3244 (3020–3983), P < 0.001, resp.). All hormone levels and muscle fibre size (n = 12) remained stable throughout the study. Age-adjusted IGF-1 was associated with type 1 and 2 fibre sizes (P < 0.05). Conclusion. Patients' total testosterone values were normal due to markedly increased LH values, which suggest a compensated primary insufficiency of the testosterone producing Leydig cell. Even though testosterone values were normal, resistance training was not associated with muscle hypertrophy. This trial is registered with ISRCTN72099857

Musculoskeletal pain reported by mobile patients with chronic kidney disease

Abstract Background Musculoskeletal pain has been reported as a clinical problem in patients with chronic kidney disease (CKD). The purpose of this study was to compare the frequency of musculoskeletal pain in patients with CKD and no mobility problems with a general population and to investigate the impact of pain on quality of life (QOL), physical activity and physical function. Methods Patients with CKD Stages 4 and 5 with or without a dialysis treatment and no mobility problems were included. Musculoskeletal pain in the shoulder/neck, back/low back and limbs and level of physical activity were measured using the Danish Health and Morbidity Survey and coded into dichotomous answers. QOL and physical function were measured using the kidney disease QOL questionnaire and the 30-s chair stand test, respectively. Data for the general population were collected in national registers and adjusted for age, gender and region. Results The patients (n = 539) had a mean age of 66 [95% confidence interval (CI) 65–67] years, 62% were men and they were treated with haemodialysis (HD) (n = 281), peritoneal dialysis (n = 62) or without dialysis (n = 196). The frequency of reported musculoskeletal pain in the patients did not exceed pain reported by the general population [e.g. pain in the limbs in patients undergoing HD versus a matched general population, 61% versus 63% (P = 0.533), respectively]. Pain in all measured body sites was associated with reduced QOL [e.g. pain in the limbs associated with a physical component scale β of −8.2 (95% CI −10.3 to −6.0), P &amp;lt; 0.001]. Pain in the limbs was associated with a reduced number of repetitions in the 30-s chair stand test [mean −1.7 (95% CI −3.0 to −0.4), P = 0.009]. Pain in the shoulder/neck was associated with reduced odds of being physically active [odds ratio 0.6 (95% CI 0.4 to 0.9); P = 0.022]. Conclusions Musculoskeletal pain was not more frequently reported by patients with CKD and no mobility problems compared with the general population. However, as musculoskeletal pain was reported by up to two-thirds of the patient sample, healthcare professionals should remember to focus on this issue. The patients’ pain was associated with negative impacts on QOL, level of physical activity and physical function. </jats:sec