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result(s) for
"Premkumar, Prasanna"
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Global prevalence of norovirus in cases of gastroenteritis: a systematic review and meta-analysis
by
Parashar, Umesh D
,
Premkumar, Prasanna
,
Lopman, Benjamin A
in
Biological and medical sciences
,
Caliciviridae Infections - epidemiology
,
Caliciviridae Infections - virology
2014
Despite substantial decreases in recent decades, acute gastroenteritis causes the second greatest burden of all infectious diseases worldwide. Noroviruses are a leading cause of sporadic cases and outbreaks of acute gastroenteritis across all age groups. We aimed to assess the role of norovirus as a cause of endemic acute gastroenteritis worldwide.
We searched Embase, Medline, and Global Health databases from Jan 1, 2008, to March 8, 2014, for studies that used PCR diagnostics to assess the prevalence of norovirus in individuals with acute gastroenteritis. We included studies that were done continuously for 1 year or more from a specified catchment area (geographical area or group of people), enrolled patients who presented with symptoms of acute gastroenteritis, and used PCR-based diagnostics for norovirus on all stool specimens from patients with acute gastroenteritis. The primary outcome was prevalence of norovirus among all cases of gastroenteritis. We generated pooled estimates of prevalence by fitting linear mixed-effect meta-regression models.
Of 175 articles included, the pooled prevalence of norovirus in 187 336 patients with acute gastroenteritis was 18% (95% CI 17–20). Norovirus prevalence tended to be higher in cases of acute gastroenteritis in community (24%, 18–30) and outpatient (20%, 16–24) settings compared with inpatient (17%, 15–19, p=0·066) settings. Prevalence was also higher in low-mortality developing (19%, 16–22) and developed countries (20%, 17–22) compared with high-mortality developing countries (14%, 11–16; p=0·058). Patient age and whether the study included years of novel strain emergence were not associated with norovirus prevalence.
Norovirus is a key gastroenteritis pathogen associated with almost a fifth of all cases of acute gastroenteritis, and targeted intervention to reduce norovirus burden, such as vaccines, should be considered.
The Foodborne Disease Burden Epidemiology Reference Group (FERG) of WHO and the Government of the Netherlands on behalf of FERG.
Journal Article
Functional principal component analysis for identifying the child growth pattern using longitudinal birth cohort data
by
Antonisamy, Belavendra
,
Karuppusami, Reka
,
Premkumar, Prasanna S.
in
Analysis
,
Birth Cohort
,
Body Height
2022
Background
Longitudinal studies are important to understand patterns of growth in children and limited in India. It is important to identify an approach for characterising growth trajectories to distinguish between children who have healthy growth and those growth is poor. Many statistical approaches are available to assess the longitudinal growth data and which are difficult to recognize the pattern. In this research study, we employed functional principal component analysis (FPCA) as a statistical method to find the pattern of growth data. The purpose of this study is to describe the longitudinal child growth trajectory pattern under 3 years of age using functional principal component method.
Methods
Children born between March 2002 and August 2003 (
n
= 290) were followed until their third birthday in three neighbouring slums in Vellore, South India. Field workers visited homes to collect details of morbidity twice a week. Height and weight were measured monthly from 1 month of age in a study-run clinic. Longitudinal child growth trajectory pattern were extracted using Functional Principal Component analysis using B-spline basis functions with smoothing parameters. Functional linear model was used to assess the factors association with the growth functions.
Results
We have obtained four FPCs explained by 86.5, 3.9, 3.1 and 2.2% of the variation respectively for the height functions. For height, 38% of the children’s had poor growth trajectories. Similarly, three FPCs explained 76.2, 8.8, and 4.7% respectively for the weight functions and 44% of the children’s had poor growth in their weight trajectories. Results show that gender, socio-economic status, parent’s education, breast feeding, and gravida are associated and, influence the growth pattern in children.
Conclusions
The FPC approach deals with subjects’ dynamics of growth and not with specific values at given times. FPC could be a better alternate approach for both dimension reduction and pattern detection. FPC may be used to offer greater insight for classification.
Journal Article
Large cohort study of postnatal events over 18 months in a not-for-profit referral centre in Vellore, South India
by
Shabeer, Muhamed
,
George, Anne
,
Abraham, Sunil
in
Adult
,
Antibiotics
,
Breast Feeding - statistics & numerical data
2025
ObjectiveTo assess maternal medical conditions, physical and surgical ailments, contraceptive use and barriers to its use, maternal mental health, neonatal health, breastfeeding practices and available social support in the postpartum period.DesignA prospective cohort study.SettingA large tertiary care centre.Participants12 245 women who delivered after 22 weeks gestation in the year 2022.InterventionsThree pre-specified exposures, namely mode of delivery, presence of significant risk factors and preterm delivery within the cohort, were used to identify potential groups of women who would need additional support.The primary and secondary outcome measuresThe primary outcome was the number of unscheduled visits by the mother or child and the indications for these visits.The secondary outcomes in mothers included unhealed wound sites, anaemia, increase in body mass index (BMI) by >3, persistent high blood pressure, pain in the abdomen or pelvis, urinary or bowel problems, musculoskeletal pain, abnormal maternal mental health, breast-related issues and barriers to breastfeeding, contraceptive use and sexual activity.ResultsOnly 2% of women and children were lost to follow-up. Nine women and 75 babies died. The majority of infant deaths were related to serious congenital diseases. Unscheduled visits to the health facility were seen in 44% of the cohort, most commonly for upper respiratory infections and fever in the mother and baby. 41 mothers and 741 infants needed admission to hospital. Hospitalisation was more common in those with risk factors or preterm delivery. High blood pressure was seen in 3 to 4% and anaemia in 4% of the cohort. Wound infection was seen in 3 to 4% and urinary incontinence in 2% of women. Wound infection was more common with instrumental delivery. Bowel incontinence was rare. A fourth of the cohort had musculoskeletal pain, especially back pain, which was more common after caesarean delivery. Only 5.5% of the cohort had unsatisfactory mental health, and these women were more likely to have abnormal mental health scores with the NICE Questionnaire at screening. The family APGAR of the cohort was 9/10, and 95% belonged to the middle-income group. 2.6% of neonates had delayed milestones, and this was more common in the group with risk factors and preterm delivery.ConclusionHealthcare utilisation was mainly for minor complaints. Re-admissions were rare, as intrapartum and immediate postpartum care were optimal. Women who delivered by caesarean section or delivered a preterm child needed additional support in the postpartum phase. NICE Questionnaire is a quick and easy screening tool to identify unsatisfactory mental health and should be used before discharge, postnatally, even in busy settings. The implementation of formal telephonic support 24 hours a day in birthing facilities should be explored in the future. Holistic postnatal care of mother and child during the immunisation of the baby would be the best opportunity to improve the quality and coverage of care in the postnatal phase.Trial registration numberCTRI/2022/03/041343.
Journal Article
Handling missing outcomes in time-to-event analyses in randomised controlled trials: a scoping review with a focus on multiple imputation
by
Mohan, Venkata Raghava
,
Karuppasamy, Saravanaraj
,
Premkumar, Prasanna Samuel
in
Clinical trials
,
Data Interpretation, Statistical
,
Health Sciences
2025
Background
Randomised Controlled Trials (RCTs) are the gold standard for evaluating treatment effects. However, missing outcomes can threaten the validity of the results. Missing data pose a unique challenge in time-to-event analyses, where the event time may be censored rather than completely missing. Proper handling of missing event times is crucial to ensure unbiased and reliable conclusions in RCTs. This scoping review examines how missing outcomes in time-to-event studies have been addressed in high-impact medical journals and evaluates the implementation and reporting of multiple imputation (MI) techniques in RCTs.
Method
This scoping review assessed methods for handling missing time-to-event outcomes in RCTs published between 2019 and 2024 in three high-impact medical journals: The New England Journal of Medicine, The Lancet, and The Journal of the American Medical Association. Studies were reviewed to identify whether missing outcome data were present and, if so, which methods were used to handle them. Studies that applied MI were examined in detail to assess how the MI approach was implemented and reported. The review also explored theoretical approaches for imputing censored event times.
Results
A total of 834 articles were identified through a PubMed search. After screening, 383 RCTs underwent full-text review. Of these, 354 (92.4%) had no or < 10% missing outcomes without imputation. The remaining 29 studies (7.6%) addressed missing data using statistical approaches: 12 applied MI, 10 used complete case analysis, 6 conducted best-/worst-case sensitivity analyses, and 1 used a propensity score-based method. MI approaches varied, with some studies lacking detailed reporting.
Conclusion
In RCTs with survival outcomes, properly handling missing event times is essential. This scoping review reveals that, despite the availability of statistical methods, the treatment of missing time-to-event outcomes remains underutilised and often poorly documented. While many studies reported non-administrative censoring, limited information was provided on whether such censoring was informative or non-informative. Additionally, the reporting of MI techniques is frequently insufficient. These findings highlight a critical gap in the handling and reporting of missing outcomes in survival analysis. Strengthening these practices will enhance the reliability and reproducibility of survival analyses in RCTs.
Journal Article
Estimating the incidence of rotavirus infection in children from India and Malawi from serial anti-rotavirus IgA titres
by
Lopman, Ben
,
Bennett, Aisleen
,
Heinsbroek, Ellen
in
Biology and Life Sciences
,
Children
,
Confidence intervals
2017
Accurate estimates of rotavirus incidence in infants are crucial given disparities in rotavirus vaccine effectiveness from low-income settings. Sero-surveys are a pragmatic means of estimating incidence however serological data is prone to misclassification. This study used mixture models to estimate incidence of rotavirus infection from anti-rotavirus immunoglobulin A (IgA) titres in infants from Vellore, India, and Karonga, Malawi. IgA titres were measured using serum samples collected at 6 month intervals for 36 months from 373 infants from Vellore and 12 months from 66 infants from Karonga. Mixture models (two component Gaussian mixture distributions) were fit to the difference in titres between time points to estimate risk of sero-positivity and derive incidence estimates. A peak incidence of 1.05(95% confidence interval [CI]: 0.64, 1.64) infections per child-year was observed in the first 6 months of life in Vellore. This declined incrementally with each subsequent time interval. Contrastingly in Karonga incidence was greatest in the second 6 months of life (1.41 infections per child year [95% CI: 0.79, 2.29]). This study demonstrates that infants from Vellore experience peak rotavirus incidence earlier than those from Karonga. Identifying such differences in transmission patterns is important in informing vaccine strategy, particularly where vaccine effectiveness is modest.
Journal Article
Role of Adjunctive corticoSTEROIDs on clinical outcomes in severe Scrub typhus pneumonitis: ASTEROIDS study protocol – a randomised controlled trial
by
Ray, Sumit
,
Krishna, Bhuvana
,
Chaudhry, Dhruva
in
Adult intensive & critical care
,
Clinical outcomes
,
Clinical Trial
2025
IntroductionRecent studies have demonstrated a beneficial role of steroids in severe community-acquired pneumonia, severe COVID-19 infection and acute respiratory distress syndrome (ARDS) of diverse aetiology. This multicentre randomised controlled trial in severe scrub typhus pneumonitis and ARDS will compare the effects of 6 mg of dexamethasone once per day with placebo, in addition to standard treatment, on ventilator-free days (VFD), mortality and ventilatory requirement.Methods and analysisThe study, involving six sites, will recruit 440 patients with severe scrub typhus pneumonitis or ARDS to concealed, block-randomised, site-specific assignment of dexamethasone or placebo for 4–7 days. The primary outcome will be VFD, defined as days alive and free of ventilation at 28 days. Secondary outcomes will include 28-day mortality, need and duration of ventilation, and treatment failure, defined as death, or escalation of respiratory support from simple devices (nasal cannula, mask) to non-invasive or invasive ventilation, or the use of open-labelled steroids for worsening shock. The study will also ascertain if antinuclear antibody (ANA) expression during the acute phase of illness will predict steroid responsiveness. Subgroup analyses will be conducted a priori on ANA expression and the need for ventilation. All analyses will be conducted on an intention-to-treat basis. The trial, which commenced in April 2025, would clarify the role of corticosteroids in scrub typhus pneumonitis.Ethics and disseminationThe Institutional Review Board and Ethics Committee of the lead site, Christian Medical College, Vellore, India, has approved the study (IRB Min No 15920 (INTERVE) dated 22 November 2023). The remaining five sites have obtained approval from their respective ethics committees. Study results will be published in an international peer-reviewed journal.Trial registration numberCTRI/2024/12/077709. Registered 5 December 2024.
Journal Article
Exclusive breastfeeding practices among mothers in urban slum settlements: pooled analysis from three prospective birth cohort studies in South India
by
Kang, Gagandeep
,
Velusamy, Vasanthakumar
,
Premkumar, Prasanna S.
in
Behavior
,
Breast feeding
,
Breastfeeding & lactation
2017
Background
The World Health Organization (WHO) recommends six months of exclusive breastfeeding. Despite documented health, social and economic benefits, the practice of exclusive breastfeeding is quite low and information on influencing factors is limited especially from slum settlements. Our goal is to assess the prevalence and evaluate factors associated with early cessation of exclusive breastfeeding in the first six months of life among mothers in urban slums of Vellore, Southern India.
Methods
We pooled data from three similar birth cohort studies (
n
= 1088) conducted between 2002 and 2009. Breastfeeding information was obtained soon after birth and then from follow-up home visits conducted once every two weeks by the field workers. Multivariable Cox regression analyses were used to assess factors associated with early cessation of exclusive breastfeeding.
Results
The prevalence of exclusive breastfeeding for the first six months was 11.4%, based on prospective data since birth. Results from multivariable analyses revealed maternal education (Adjusted Hazard Ratio [AHR] 1.18 , 95% CI 1.03, 1.35), pucca type of house (AHR 1.25 , 95% CI 1.10, 1.43), two or more number of children in the family (AHR 1.26 , 95% CI 1.10, 1.43), joint family structure (AHR 1.20 , 95% CI 1.02, 1.40) and birth during summer (AHR 1.16, 95% CI 1.01, 1.31) were associated with early cessation of exclusive breastfeeding in the first six months.
Conclusions
Our results indicate that exclusive breastfeeding rates are well below the recommended levels. Educational interventions providing comprehensive breastfeeding information to mothers and their families can be evaluated to assess its effect on improving infant feeding practices.
Journal Article
Natural History of Cryptosporidiosis in a Birth Cohort in Southern India
by
Jeyavelu, Nithya
,
Muliyil, Jayaprakash
,
Kang, Gagandeep
in
ARTICLES AND COMMENTARIES
,
Cohort Studies
,
Cryptosporidiosis
2017
Background. Cryptosporidium is a leading cause of moderate to severe childhood diarrhea in resource-poor settings. Understanding the natural history of cryptosporidiosis and the correlates of protection are essential to develop effective and sustainable approaches to disease control and prevention. Methods. Children (N = 497) were recruited at birth in semiurban slums in Vellore, India, and followed for 3 years with twice-weekly home visits. Stool samples were collected every 2 weeks and during diarrheal episodes were tested for Cryptosporidium species by polymerase chain reaction (PCR). Serum samples obtained every 6 months were evaluated for seroconversion, defined as a 4-fold increase in immunoglobulin G directed against Cryptosporidium gp15 and/or Cp23 antigens between consecutive sera. Results. Of 410 children completing follow-up, 397 (97%) acquired cryptosporidiosis by 3 years of age. PCR identified 1053 episodes of cryptosporidiosis, with an overall incidence of 0.86 infections per child-year by stool and serology. The median age for the first infection was 9 (interquartile range, 4–17) months, indicating early exposure. Although infections were mainly asymptomatic (693 [66%]), Cryptosporidium was identified in 9.4% of diarrheal episodes. The proportion of reinfected children was high (81%) and there was clustering of asymptomatic and symptomatic infections (P < .0001 for both). Protection against infection increased with the order of infection but was only 69% after 4 infections. Cryptosporidium hominis (73.3%) was the predominant Cryptosporidium species, and there was no species-specific protection. Conclusions. There is a high burden of endemic cryptosporidiosis in southern India. Clustering of infection is suggestive of host susceptibility. Multiple reinfections conferred some protection against subsequent infection.
Journal Article
Incidence and risk factor evaluation of exposure keratopathy in critically ill patients: A cohort study
by
Premkumar, Prasanna Samuel, M.Sc., PhD
,
Kuruvilla, Shilpa, MS
,
Thomas, Lovely, MBBS DNB
in
Adult
,
Anesthesia
,
Cohort Studies
2015
Abstract Purpose Recent emphasis on eye care in intensive care unit (ICU) patients has translated to eye assessment being part of routine care. In this setting, we determined the incidence, risk factors, and resolution time of exposure keratopathy. Methods In this prospective cohort study, 301 patients were examined within 24 hours of ICU admission and subsequently daily by an ophthalmologist till death or discharge. Eyelid position, conjunctival and corneal changes, treatment, and outcome data were collected. Results Admission diagnoses included febrile illnesses (35.2%) and respiratory failure (32.6%); 84.1% were ventilated. Forty-nine patients had exposure keratopathy (bilateral = 35, unilateral = 14) at admission; 35 patients developed new onset keratopathy (incidence 13.2%) 4.6 ± 2.6 days after ICU admission. In 67 patients, keratopathy was mild (punctate epithelial erosions). Macroepithelial defects (n = 9), stromal whitening with epithelial defect (n = 3), and stromal scar (n = 3) were infrequent. None developed microbial keratitis. On multivariate logistic regression analysis, eyelid position (odds ratio, 2.93; 95% confidence interval, 1.37-6.25), and ventilation duration (odds ratio, 1.11; 95% confidence interval, 1.04-1.19) were strongly associated with the development of keratopathy after ICU admission. Keratopathy resolved in 3.6 ± 4.5 days. Conclusions Severe exposure keratopathy is infrequent in a protocolized ICU setting. Eyelid position and duration of ventilation are associated with exposure keratopathy.
Journal Article
Persistent bacteremia predicts poor outcomes among neutropenic patients with carbapenem-resistant gram-negative bloodstream infections receiving appropriate therapy
by
Shankar, Chaitra
,
John, Grace Mary
,
Korula, Anu
in
Adolescent
,
Anti-Bacterial Agents - therapeutic use
,
Antibacterial agents
2023
Purpose
Identifying persistent bacteremia early in patients with neutropenia may improve outcome. This study evaluated the role of follow-up blood cultures (FUBC) positivity in predicting outcomes among patients with neutropenia and carbapenem-resistant gram-negative bloodstream infections (CRGNBSI).
Methods
This retrospective cohort study conducted between December 2017 and April 2022 included patients more than 15 years old with neutropenia and CRGNBSI, who survived for ≥ 48 h, receiving appropriate antibiotic therapy and had FUBCs. Patients with polymicrobial bacteremia within 30 days were excluded. The primary outcome was 30 day mortality. Persistent bacteremia, septic shock, recovery from neutropenia, prolonged or profound neutropenia, requirement of intensive care and dialysis, and initiation of appropriate empirical therapy were also studied.
Results
In our study cohort of 155 patients, the 30 day mortality rate was 47.7%. Persistent bacteremia was common in our patient cohort (43.8%). Carbapenem resistant isolates identified in the study were K.pneumoniae (80%), E.coli (12.26%), P.aeruginosa (5.16%), A.baumanii (1.94%) and E.cloacae (0.65%). The median time for sending a FUBC was 2 days (IQR, 1–3 days). Patients with persistent bacteremia had higher mortality than those without (56.76% versus 32.1%; p < 0.001). Appropriate initial empirical therapy was given to 70.9%. Recovery from neutropenia occurred in 57.4% while 25.8% had prolonged or profound neutropenia. Sixty-nine percent (107/155) had septic shock and needed intensive care; 12.2% of patients required dialysis. Non-recovery from neutropenia (aHR, 4.28; 95% CI 2.53–7.23), presence of septic shock (aHR, 4.42; 95%CI 1.47–13.28), requirement of intensive care (aHR,3.12;95%CI 1.23–7.93), and persistent bacteremia (aHR,1.74; 95%CI 1.05–2.89) significantly predicted poor outcomes in multivariable analysis.
Conclusion
FUBC showing persistent bacteremia predicted poor outcomes among neutropenic patients with carbapenem-resistant gram-negative bloodstream infections (CRGNBSI) and should be routinely reported.
Journal Article