Plasma glucose in screening for diabetes and pre-diabetes: how much is too much? Analysis of fasting plasma glucose and oral glucose tolerance test in Sri Lankans.

BACKGROUND: Fasting plasma glucose (FPG) is the most commonly used screening tool for diabetes in Sri Lanka. Cut-off values from American Diabetes Association recommendations are adopted in the absence of local data. We aimed to establish FPG cut offs for Sri Lankans to screen for diabetes and pre-diabetes. METHODS: Data on FPG and diabetes/pre-diabetes status were obtained from Sri Lanka Diabetes and Cardiovascular Study (SLDCS), a community based island wide observational study conducted in 2005-6. Sensitivity specificity and area under the ROC curve were calculated for different FPG values. RESULTS: Study included 4014 community dwelling people after excluding people already on treatment for diabetes or pre-diabetes. Mean age was 45.3 (± 15) years and 60.4% were females. FPG cut off of 5.3 mmol/L showed better sensitivity and specificity than 5.6 mmol/L in detecting diabetes (87.8% and 84.4% Vs 80.8% and 92.1%) and pre-diabetes (54.7% and 87.0% Vs 43.8% and 94.2%). CONCLUSIONS: A lower FPG cut off of 5.3 mmol/L has a better sensitivity and acceptable specificity in screening for diabetes and pre-diabetes in Sri Lankan adults.

Waist to height ratio: a better anthropometric marker of diabetes and cardio-metabolic risks in South Asian adults.

AIMS: Obesity associated metabolic diseases have reached epidemic levels in many South Asian countries. Conventional anthropometric indices have poor sensitivity and specificity for detecting people with increased metabolic risks. The aim of this study was to investigate and compare WHtR (Waist to Height Ratio) as a marker of diabetes and cardio-metabolic risks with existing classical anthropometric indices such as; Body Mass Index (BMI), Waist Circumference (WC) and Waist to Hip Ratio (WHR) in a large sub-population of ethnic South Asians. METHODS: A total of 5000 subjects recruited from a nationally representative community-based sample using multi-stage random cluster-sampling method. Anthropometric, biochemical and clinical parameters were measured. Receiver-operating characteristic (ROC) curves were performed and area under the curve (AUC) was calculated for each anthropometric index. RESULTS: Sample size was 4485. The mean WHtR in all adults was 0.496 (±0.077), males (0.477±0.065) had a significant lower WHtR than females (0.508±0.081) (p<0.001). WHtR had the highest correlation with metabolic parameters. In all adults, males and females the AUC of WHtR was significantly higher than that of BMI, WC and WHR in diabetes mellitus, pre-diabetes, hypertension, metabolic syndrome and hypercholesterolemia. Mean age, fasting blood glucose, 2-h post prandial blood Glucose, total cholesterol, LDL cholesterol, triglycerides, systolic blood pressure and diastolic blood pressure were all significantly higher among all adults, males and females with WHtR≥0.5. CONCLUSIONS: WHtR is a simple and effective anthropometric index to identify obesity associated metabolic risks among Sri Lankan adults.

Derivation of anthropometric cut-off levels to define CVD risk in Sri Lankan adults.

Obesity is associated with increased cardiovascular risk. Anthropometric cut-off values derived for Caucasians may not be applicable to other populations. The main objective of the present study was to derive population-specific anthropometric cut-off values to define high CVD risk for Sri Lankan adults. A nationally representative sample of 4474 non-institutionalised adults aged ≥ 18 years was analysed. Cut-off values to provide optimum sensitivity and specificity were derived using receiver-operating characteristic curve analysis. BMI, waist circumference (WC), waist-to-hip ratio (WHR), blood pressure and overnight fasting venous blood samples were collected to measure glucose, HDL-cholesterol and TAG. An oral glucose tolerance test was also performed. The results suggested that the age-adjusted BMI, WC and WHR were significantly associated with all cardiovascular risk factors (P < 0·001). Cut-off values for BMI, WC and WHR for males were 20·7 kg/m2, 76·5 cm and 0·89, respectively. The respective values for females were 22·0 kg/m2, 76·3 cm and 0·85. The common cut-off value for BMI for males and females was 21·5 kg/m2. Similarly, WC and WHR cut-off values for both males and females were 76·3 cm and 0·87, respectively. The Asian and Caucasian anthropometric cut-off levels showed lower sensitivity and higher false negative percentage compared with newly derived cut-off levels. In conclusion, BMI, WC and WHR were all associated with increased CVD risk. We propose the following anthropometric cut-off points to determine high CVD risk level for Sri Lankan adults: BMI ≥ 21·5 kg/m2, WC ≥ 76 cm and WHR ≥ 0·85 (women) and 0·90 (men).

Prevalence of overweight and obesity in Sri Lankan adults.

The aim of the study was to determine the prevalence of overweight, obesity and abdominal obesity, and the underlying socio-demographic correlates among Sri Lankan adults. Data were from 4532 adults aged ≥18 years randomly selected for a national level study on diabetes and cardiovascular disease. Weight, height and waist circumference (WC) were measured and body mass index (BMI) calculated. The mean (95% confidence interval) BMI and WC were 21.1 kg m(-2) (20.9-21.3), 22.3 kg m(-2) (22.1-22.4) and 78.0 cm (77.5-78.6) and 77.5 cm (77.0-78.0) for males and females, respectively. According to the proposed World Health Organization cut-off values for Asians, the percentage of Sri Lankan adults in the overweight, obese and centrally obese categories were 25.2%, 9.2% and 26.2%, respectively. Based on the cut-offs for Caucasians, these were 16.8%, 3.7% and 10.8%. Our findings were compatible with prevalence of obesity in regional countries. In addition, female sex, urban living, higher education, higher income and being in the middle age were shown to be associated with overweight and obesity in Sri Lankans. In conclusion, we have documented a relatively high prevalence of overweight and obesity, particularly, abdominal obesity among adults in Sri Lanka which is a middle-income country. Urgent public health interventions are needed to control the problem at an early stage.

Poisoning with the S-Alkyl organophosphorus insecticides profenofos and prothiofos.

BACKGROUND: Many organophosphorus (OP) insecticides have either two O-methyl or two O-ethyl groups attached to the phosphorus atom. This chemical structure affects their responsiveness to oxime-induced acetylcholinesterase (AChE) reactivation after poisoning. However, several OP insecticides are atypical and do not have these structures. AIM: We aimed to describe the clinical course and responsiveness to therapy of people poisoned with two S-alkyl OP insecticides-profenofos and prothiofos. DESIGN: We set up a prospective cohort of patients with acute profenofos or prothiofos self-poisoning admitted to acute medical wards in two Sri Lankan district hospitals. Clinical observation was carried out throughout their inpatient stay; blood samples were taken in a subgroup for assay of cholinesterases and insecticide. RESULTS: Ninety-five patients poisoned with profenofos and 12 with prothiofos were recruited over 5 years. Median time to admission was 4 (IQR 3-7) h. Eleven patients poisoned with profenofos died (11/95; 11.6%, 95% CI 5.9-20); one prothiofos patient died (1/12; 8.3%, 95% CI 0.2-38). Thirteen patients poisoned with profenofos required intubation for respiratory failure (13/95; 13.7%, 95% CI 7.5-22); two prothiofos-poisoned patients required intubation. Both intubations and death occurred late compared with other OP insecticides. Prolonged ventilation was needed in those who survived-a median of 310 (IQR 154-349) h. Unexpectedly, red cell AChE activity on admission did not correlate with clinical severity-all patients had severe AChE inhibition (about 1% of normal) but most had only mild cholinergic features, were conscious, and did not require ventilatory support. CONCLUSION: Compared with other commonly used OP insecticides, profenofos and prothiofos are of moderately severe toxicity, causing relatively delayed respiratory failure and death. There was no apparent response to oxime therapy. The lack of correlation between red cell AChE activity and clinical features suggests that this parameter may not always be a useful marker of synaptic AChE activity and severity after OP pesticide poisoning.

Frequent and potentially fatal envenoming by hump-nosed pit vipers (Hypnale hypnale and H. nepa) in Sri Lanka: lack of effective antivenom.

In a prospective study of snake bites involving 10 hospitals in Sri Lanka, 302 (35%) of 860 patients with bites by identified snakes proved to have been bitten by hump-nosed pit vipers (301 by Hypnale hypnale and 1 by H. nepa). Most victims were males aged between 11 years and 50 years who had been bitten on their feet or ankles while walking at night close to their homes. There was local swelling in 276 (91%) and local necrosis in 48 (16%). Eleven (4%) required amputation of fingers or toes and 12 (4%) received skin grafts. In 117 patients (39%) blood incoagulability was first detected between 15 min and 48 h after the bite, and in 116 of them this was present on admission to hospital. Spontaneous systemic bleeding was observed in 55 patients (18%). Acute renal failure developed in 10%, five of whom died to give an overall case fatality rate of 1.7%. Thus, bites by hump-nosed pit vipers can cause debilitating local and fatal systemic envenoming. In Sri Lanka and southwestern India where bites by these snakes are common, the only available antivenoms (raised against cobra, krait, Russell's viper and saw-scaled viper venoms) are ineffective and carry a high risk of reactions.

The diabetes epidemic in Sri Lanka - a growing problem.

Diabetes mellitus, which was once considered a disease of the developed world, has become a worldwide pandemic, with two thirds of the global diabetic population living in the developing countries. Local studies show a definite upward trend in the prevalence of diabetes mellitus. The earliest available study on a rural community in 1990 reported a prevalence of 2.5%. The largest-ever study on the diabetes prevalence in Sri Lanka was published in 2005. It showed a prevalence of 14.2% among males and 13.5% among females. The World Health Organisation and the International Diabetic Federation estimates and forecasts are much lower than the available local prevalence rates, and what may be predicted from the prevalence rates in South India. Further research is necessary to investigate the exact underlying mechanisms for the South Asian epidemic. Wider preventive programmes need to be urgently implemented to stem the tide.

Respiratory failure in acute organophosphorus pesticide self-poisoning.

BACKGROUND: Acute organophosphorus (OP) pesticide poisoning is a major clinical problem in the developing world. Textbooks ascribe most deaths to respiratory failure occurring in one of two distinct clinical syndromes: acute cholinergic respiratory failure or the intermediate syndrome. Delayed failure appears to be due to respiratory muscle weakness, but its pathophysiology is unclear. AIM: To describe the clinical patterns of OP-induced respiratory failure, and to determine whether the two syndromes are clinically distinct. DESIGN: Prospective study of 376 patients with confirmed OP poisoning. METHODS: Patients were observed throughout their admission to three Sri Lankan hospitals. Exposure was confirmed by butyrylcholinesterase and blood OP assays. RESULTS: Ninety of 376 patients (24%) required intubation: 52 (58%) within 2 h of admission while unconscious with cholinergic features. Twenty-nine (32%) were well on admission but then required intubation after 24 h while conscious and without cholinergic features. These two syndromes were not clinically distinct and had much overlap. In particular, some patients who required intubation on arrival subsequently recovered consciousness but could not be extubated, requiring ventilation for up to 6 days. DISCUSSION: Respiratory failure did not occur as two discrete clinical syndromes within distinct time frames. Instead, the pattern of failure was variable and overlapped in some patients. There seemed to be two underlying mechanisms (an early acute mixed central and peripheral respiratory failure, and a late peripheral respiratory failure) rather than two distinct clinical syndromes.