Bolus administration of intravenous glucose in the treatment of hyperkalemia: a randomized controlled trial.

BACKGROUND: Hyperkalemia is a common medical emergency that may result in serious cardiac arrhythmias. Standard therapy with insulin plus glucose reliably lowers the serum potassium concentration ([K(+)]) but carries the risk of hypoglycemia. This study examined whether an intravenous glucose-only bolus lowers serum [K(+)] in stable, nondiabetic, hyperkalemic patients and compared this intervention with insulin-plus-glucose therapy. METHODS: A randomized, crossover study was conducted in 10 chronic hemodialysis patients who were prone to hyperkalemia. Administration of 10 units of insulin with 100 ml of 50% glucose (50 g) was compared with the administration of 100 ml of 50% glucose only. Serum [K(+)] was measured up to 60 min. Patients were monitored for hypoglycemia and EKG changes. RESULTS: Baseline serum [K(+)] was 6.01 ± 0.87 and 6.23 ± 1.20 mmol/l in the insulin and glucose-only groups, respectively (p = 0.45). At 60 min, the glucose-only group had a fall in [K(+)] of 0.50 ± 0.31 mmol/l (p < 0.001). In the insulin group, there was a fall of 0.83 ± 0.53 mmol/l at 60 min (p < 0.001) and a lower serum [K(+)] at that time compared to the glucose-only group (5.18 ± 0.76 vs. 5.73 ± 1.12 mmol/l, respectively; p = 0.01). In the glucose-only group, the glucose area under the curve (AUC) was greater and the insulin AUC was smaller. Two patients in the insulin group developed hypoglycemia. CONCLUSION: Infusion of a glucose-only bolus caused a clinically significant decrease in serum [K(+)] without any episodes of hypoglycemia.

Gamma-glutamyltransferase, insulin resistance and cardiometabolic risk profile in a middle-aged African population.

BACKGROUND: Mechanisms linking liver functions with cardiometabolic risk may involve insulin resistance (IR) and non-alcoholic fatty liver disease. We assessed the associations of gamma-glutamyltransferase (GGT) levels with IR and metabolic syndrome (MetS) in an adult South African urban cohort. METHODS: 1198 participants aged >15 years (297 men) were drawn from the Bellville-South suburb (Cape Town). The homeostatic model assessment of insulin (HOMA-IR), ß-cells function (HOMA-B%), fasting insulin resistance index (FIRI) and the quantitative insulin-sensitivity check index (QUICKI) were calculated, and MetS defined according to the Join Interim Statement 2009 criteria. Associations of GGT levels with covariates were assessed on a continuous scale and across sex-specific quarters of GGT, with adjustment for confounders via generalized linear and logistic regressions. RESULTS: Indicators of IR (HOMA-IR, FIRI and fasting insulin) increased, whereas those for insulin sensitivity (Sib and QUICKI) diminished significantly linearly and across increasing GGT quarters. In multivariable-adjusted models, adjustment for sex, age, BMI, cigarette smoking and alcohol intake yielded the strongest, significant associations between GGT and all markers of IR/IS and glycemia excluding glucose insulin ratio. In a similar level of adjustments, with/without further adjustment for markers of IR/insulin sensitivity, the prevalence of MetS significantly increased across quarters of GGT. CONCLUSIONS: GGT levels were independently associated with insulin sensitivity and MetS in this population. Unaccounted, chronic elevation of GGT may therefore be a cue to screen and monitor individuals for MetS and diabetes, and may warrant consideration as an indicator of high risk for the development of these metabolic disorders.

High prevalence of diabetes mellitus and metabolic syndrome in a South African coloured population: baseline data of a study in Bellville, Cape Town.

OBJECTIVE: The coloured population has the second-highest prevalence of diabetes in South Africa. However, the data were based on a study conducted almost 20 years ago in a peri-urban coloured population of the Western Cape. We aimed to determine the prevalence of diabetes mellitus and metabolic syndrome in an urban coloured population in South Africa. DESIGN: In a cross-sectional survey, 642 participants aged ≥31 years were drawn from an urban community of Bellville South, Cape Town, from mid-January 2008 to March 2009. Type 2 diabetes was assessed according to the WHO criteria, and metabolic syndrome was based on the International Diabetes Federation (IDF), ATP III and 2009 Joint Interim Statement (JIS) definition. RESULTS: The crude prevalence of 28.2% (age-adjusted 26.3%, 95% confidence interval (CI) 22.0 - 30.3) for type 2 diabetes was: 4.4% (age-adjusted 3.2%, 95% CI 1.6 - 4.9) for impaired fasting glycaemia, and 15.3% (age-adjusted 15.0%, 95% CI 11.4 - 18.6) for impaired glucose tolerance. Undiagnosed type 2 diabetes was present in 18.1% (age-adjusted 16.8%, 95% CI 13.3 - 20.4). The crude prevalence of metabolic syndrome was higher with the JIS definition (62.0%) than the IDF (60.6%), and the National Cholesterol Education Program (NCEP) ATP III (55.4%). There was good overall agreement between the MetS criteria, k=0.89 (95% CI 0.85 - 0.92). CONCLUSION: The prevalence of diabetes has increased hugely in the coloured community, and the high prevalence of undiagnosed diabetes portends that cardiovascular diseases might grow to epidemic proportions in the near future in South Africa.

Polymorphisms in the non-muscle myosin heavy chain gene (MYH9) are associated with lower glomerular filtration rate in mixed ancestry diabetic subjects from South Africa.

OBJECTIVE: Though single nucleotide polymorphisms (SNPs) in the non-muscle myosin gene (MYH9) have been reported to explain most of the excess risk of nondiabetic chronic kidney disease (CKD), in African-Americans, some studies have also shown associations with diabetic end-stage renal disease. We investigated the association of MYH9 SNPs with renal traits in a mixed-ancestry South African population prone to diabetes. RESEARCH DESIGN AND METHODS: Three SNPs known to be associated with CKD (rs4821480, rs5756152 and rs12107) were genotyped using Taqman assay in 716 adults (198 with diabetes) from the Bellville-South community, Cape Town. Glomerular filtration rate was estimated (eGFR) and urinary albumin/creatinine ratio (ACR) assessed. Multivariable regressions were used to relate the SNPs with renal traits. RESULTS: Mean age was 53.6 years, with the expected differences observed in characteristics by diabetic status. Significant associations were found between rs575152 and serum creatinine, and eGFR in the total population, and in diabetic participants (all p≤0.003), but not in non-diabetics (all p≥0.16), with significant interactions by diabetes status (interaction-p≤0.009). The association with ACR was borderline in diabetic participants (p = 0.05) and non-significant in non-diabetics (p = 0.85), with significant interaction (interaction p = 0.02). rs12107 was associated with fasting-, 2-hour glucose and HbA1c in diabetic participants only (interaction-p≤0.003), but not with renal traits. CONCLUSION: MYH9 SNPs were associated with renal traits only in diabetic participants in this population. Our findings and other studies suggest that MYH9 may have a broader genetic risk effect on kidney diseases.

Monounsaturated fatty acids in blood cell membranes from patients with multiple sclerosis.

The aim of this study was to investigate whether blood cell membrane monounsaturated fatty acids were associated with inflammation and disease outcome in patients with multiple sclerosis. The fatty acid composition in peripheral blood mononuclear cell and red blood cell membranes from 26 patients and 25 controls were determined by gas chromatography. Results showed positive associations between C-reactive protein and C16:1n-7, C18:1n-7, and C24:1n-9 in membranes from controls only. In general, C18:1n-9 and C20:1n-9 showed inverse correlations, while C16:1n-7 and C18:1n-7 showed positive correlations with disease outcome. Multiple sclerosis has a known inflammatory component. There is scarcity of literature on the role of monounsaturated fatty acids in inflammation, but results from this study suggested an association in healthy subjects between monounsaturated fatty acids and C-reactive protein, even at physiologically low levels. This association was not found in the plasma from patients. Furthermore, the n-9 and n-7 fatty acids played different roles in disease outcome, and therefore warrant inclusion, together with polyunsaturated fatty acids when investigating the inflammatory aspects of the disease.