B. Siddhartha Kumar

Molecular characterization of Orientia tsutsugamushi serotypes causing scrub typhus outbreak in southern region of Andhra Pradesh, India.

Background & objectives: Scrub typhus is a vector-borne zoonotic infection caused by Orientia tsutsugamushi. Local epidemiology of the circulating serotypes of scrub typhus is not available from most parts of India. We conducted this study for the diagnosis of scrub typhus using IgM ELISA and to detect O. tsutsugamushi serotypes circulating in southern Andhra Pradesh, India. Methods: Samples were collected from patients clinically suspected to have scrub typhus and were subjected to IgM ELISA to measure IgM antibodies against O. tsutsugamushi. Nested polymerase chain reaction (PCR) was performed targeting strain-specific regions in ELISA-positive samples. Results: Of a total of 663 samples, 258 (38.91%) were found to be positive by IgM ELISA. Serotypes could be detected in 230 (34.69%) samples only. Only two serotypes, Karp and Kawasaki, were found in the serum samples, with the former being predominant. The dual infection of Karp and Kawasaki serotypes was found in seven patients. Other serotypes such as Gilliam, Kuroki and Kato were not detected in the samples. Interpretation & conclusion: The nested PCR products proved useful in presumptively identifying the endemic O. tsutsugamushi serotypes. The present study could be significant in understanding scrub typhus epidemiology in this region.

Effect of oral hypoglycaemic agents on bone metabolism in patients with type 2 diabetes mellitus & occurrence of osteoporosis

Background & objectives: Type 2 diabetes mellitus (T2DM) is considered to be a protective factor against development of osteoporosis. But oral hypoglycaemic agents (OHA) are likely to increase the risk of osteoporosis. This study was carried out to evaluate the effect of various OHA on bone mineral density (BMD) in patients with T2DM. Methods: Forty one patients (study group) with T2DM (mean age 51.9±5.5 yr; 31 females) receiving treatment with oral hypoglycaemic agents (OHA) [thiazolidinediones alone (n=14) or in combination with other OHA (n=27)] for a period of at least three consecutive years and 41 age- and gender-matched healthy controls (mean age 51.4±5.1 yr) were included in the study. A detailed clinical history was taken and all were subjected to physical examination and recording of anthropometric data. BMD was assessed for both patients and controls. Results: The mean body mass index (kg/m2) (26.5±4.90 vs 27.3 ±5.33) and median [inter-quartile range (IQR)] duration of menopause (yr) among women [6(2-12) vs 6(1-13)] were comparable between both groups. The bone mineral density (BMD; g/cm2) at the level of neck of femur (NOF) (0.761±0.112 vs 0.762±0.110), lumbar spine antero-posterior view (LSAP) (0.849±0.127 vs 0.854±0.135); median Z-score NOF {0.100[(-0.850)-(0.550)] vs -0.200[(-0.800)-(0.600)]}, LSAP {-1.200[(-1.700)-(-0.200)] vs -1.300 [(-1.85)-(-0.400)]} were also similar in study and control groups. Presence of normal BMD (9/41 vs 8/41), osteopenia (16/41 vs 18/41) and osteoporosis (16/41 vs 15/41) were comparable between the study and control groups. No significant difference was observed in the BMD, T-scores and Z-scores at NOF and LSAP among T2DM patients treated with thiazolidinediones; those treated with other OHA and controls. Interpretation & conclusions: The present findings show that the use of OHA for a period of three years or more does not significantly affect the BMD in patients with T2DM.

Provider-initiated HIV testing & counselling in incident tuberculosis cases under National TB Programme conditions at a tertiary care teaching hospital in Tirupati, south India

Background & objectives: As sparse published data are available regarding burden of human immunodeficiency virus (HIV) infection in incident tuberculosis (TB) cases at tertiary care teaching hospitals under National TB Programme conditions from India, the present study was designed to assess the proportion of referred registered TB patients who had actually undergone HIV testing and HIV-seropositivity in these. Methods: This was a study of provider-initiated HIV testing and counselling in patients registered for the treatment under Revised National TB Control Programme (RNTCP) of Government of India at a tertiary care teaching hospital in Tirupati, south India, during 2012-2013. Results: Between January 2012 and June 2013, 610 adult patients registered under RNTCP who were referred to Integrated Counselling and Testing Centre for HIV testing, were prospectively studied. Of these, 458 patients (75%) [mean age: 38.6±16.3 yr; 295 (64.4%) males] underwent HIV testing; HIV-co-infection was present in 21 (4.6%) patients. A significantly higher proportion of HIV co-infection was evident in PTB compared with EPTB [13/179 (7.2%) vs 8/279 (2.8%); respectively, P=0.038] and in previously treated patients compared to new patients [6/51 (11.8%) vs 15/407 (3.7%); respectively, P=0.009]. Interpretation & conclusions: The findings of this study showed that a higher proportion of TB patients underwent HIV testing (75%) compared to the national figure of 63 per cent in 2013-2014. HIV seropositivity (4.6%) in TB patients who underwent HIV testing was similar to the five per cent figure observed at national level during 2013-2014. The HIV status of 25 per cent of patients with incident TB still remained unknown, suggesting a need for better integration and co-ordination for effective management of HIV-TB co-infection.

Derivation & validation of glycosylated haemoglobin (HbA 1c ) cut-off value as a diagnostic test for type 2 diabetes in south Indian population

Background & Objectives: Glycosylated haemoglobin (HbA1c) has been in use for more than a decade, as a diagnostic test for type 2 diabetes. Validity of HbA1c needs to be established in the ethnic population in which it is intended to be used. The objective of this study was to derive and validate a HbA1c cut-off value for the diagnosis of type 2 diabetes in the ethnic population of Rayalaseema area of south India. Methods: In this cross-sectional study, consecutive patients suspected to have type 2 diabetes underwent fasting plasma glucose (FPG) and 2 h post-load plasma glucose (2 h-PG) measurements after a 75 g glucose load and HbA1c estimation. They were classified as having diabetes as per the American Diabetes Association criteria [(FPG ≥7 mmol/l (≥126 mg/dl) and/or 2 h-PG ≥11.1 mmol/l (≥200 mg/dl)]. In the training data set (n = 342), optimum cut-off value of HbA1c for defining type 2 diabetes was derived by receiver-operator characteristic (ROC) curve method using oral glucose tolerance test results as gold standard. This cut-off was validated in a validation data set (n = 341). Results: On applying HbA1c cut-off value of >6.3 per cent (45 mmol/mol) to the training data set, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for diagnosing type 2 diabetes were calculated to be 90.6, 85.2, 80.8 and 93.0 per cent, respectively. When the same cut-off value was applied to the validation data set, sensitivity, specificity, PPV and NPV were 88.8, 81.9, 74.0 and 92.7 per cent, respectively, although the latter were consistently smaller than the proportions for the training data set, the differences being not significant. Interpretation & conclusions: HbA1c >6.3 per cent (45 mmol/mol) appears to be the optimal cut-off value for the diagnosis of type 2 diabetes applicable to the ethnic population of Rayalaseema area of Andhra Pradesh state in south India.