Papers by Selvaraj Sivasubramaniam
Medical teacher, Jan 16, 2015
The sequential objective structured clinical exam (OSCE) is a stand-alone variation of the tradit... more The sequential objective structured clinical exam (OSCE) is a stand-alone variation of the traditional OSCE whereby all students sit a screening test. Those who pass this initial assessment undergo no further testing while weakly performing students sit an additional (sequential) test to determine their overall pass/fail status. Our aim was to determine outcomes of adopting a sequential OSCE approach using different numbers of screening stations and pass marks. We carried out a retrospective, observational study of anonymised databases of two cohorts of student outcomes from the final OSCE examination at the University of Aberdeen Medical School. Data were accessed for students (n = 388) who sat the exam in the years 2013-2014. We used Stata simulate program to compare outcomes - in terms of sensitivity and specificity - across 5000 random selections of 6-14 OSCE stations using random selections of groups of 100 students (with different screening test pass marks) versus those obtain...
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Archives of Ophthalmology
To establish the long-term, dose-response relationship between the concentration of and duration ... more To establish the long-term, dose-response relationship between the concentration of and duration of exposure to mitomycin to a decrease in intraocular pressure (IOP) and fewer complications. We performed a prospective double-masked, placebo-controlled, 1-year study evaluating the decrease in IOP and fewer complications of fornix-based trabeculectomy surgery in 300 eyes equally divided among therapy with placebo; mitomycin, 0.2 mg/ mL, applied for 2 minutes; mitomycin, 0.4 mg/mL, applied for 4 minutes; or mitomycin, 0.4 mg/mL, applied for 2 minutes. All of the eyes had vertical and horizontal cup-disc ratios greater than 0.7. We observed significant treatment-related differences in IOP, with a decrease in IOP in all 3 mitomycin-treated groups for all of the times beyond 1 month. The number of eyes achieving strict IOP control and the development of cataract suggest a possible dose-response effect for concentration and time of exposure. Progressive lens opacification was the most freq...
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British Journal of General Practice
Childhood vaccination has been vigorously debated in recent years. Professional and parental conf... more Childhood vaccination has been vigorously debated in recent years. Professional and parental confidence in the measles, mumps and rubella (MMR) vaccine in particular has been shaken, as reflected by its decreased uptake. To investigate the influence of practice type and the method of vaccination call/recall on childhood immunisation coverage. Analysis of childhood immunisation uptake rates. General practices in the Highland NHS Health Board area in Scotland. Data on the immunisation uptake of individual practices in the region were obtained from the Information and Statistics Division of NHS Scotland. Uptake of all vaccines in children reaching the age of 2 years was lower in practices using their own call/recall system than those engaged with the national system. Inducement practices achieved lower uptake than non-inducement practices for every immunisation studied, with the differences ranging from 4.7% to 7.8%. Compared with group practices, uptake of all vaccines was less for si...
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British Journal of Sports Medicine, 2002
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Rural and remote health
Farmers and farm workers have higher than expected rates of suicide and undetermined deaths in UK... more Farmers and farm workers have higher than expected rates of suicide and undetermined deaths in UK studies, and some rural areas of Scotland have higher than average male suicide rates. Firearm access seems to be an influencing factor in England and Wales. Type of farming, and farming social networks may also be important. This article describes suicide and undetermined deaths in male farmers and farm workers in Scotland from 1981-1999 using anonymised, routine data. Deaths of men aged 15-74 years from suicide or undetermined cause were identified from anonymised Scottish death records. Farmers and farm workers were identified using occupation codes. Methods of suicide used by farmers were compared with those of the general male population of the same age. A multiple linear regression was used to examine the influence of farm type, and the proportion of farmers in the working population of an area. 307 male farmers or farm workers died by suicide or undetermined cause in the time per...
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Archives of Ophthalmology
To develop and validate vision function (VF) and quality of life (QOL) instruments in patients wi... more To develop and validate vision function (VF) and quality of life (QOL) instruments in patients with cataracts in the context of large volume surgery in a developing country. The instruments were developed using a consensus approach. One hundred patients who were undergoing cataract surgery at Aravind Eye Hospital, Madurai, India, were interviewed preoperatively and 3 and 12 months postoperatively. Standard clinical procedures were followed, including measurement of visual acuity. Between-interviewer reproducibility was measured by repeated administration of the preoperative questionnaire. Within-interviewer reproducibility was measured preoperatively in a separate study of 50 patients. Preoperative scores from the VF and QOL instruments were significantly associated with visual acuity (r = 0.4). Internal reliability (Cronbach alpha) was greater than .9. Both instruments showed large changes after surgery, with effect sizes of 3 or greater for most VF scales (range, 1.8-3.7) and 1 or...
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PLoS neglected tropical diseases, 2015
The distribution of trachoma in Nigeria is spatially heterogeneous, with large-scale trends obser... more The distribution of trachoma in Nigeria is spatially heterogeneous, with large-scale trends observed across the country and more local variation within areas. Relative contributions of individual and cluster-level risk factors to the geographic distribution of disease remain largely unknown. The primary aim of this analysis is to assess the relationship between climatic factors and trachomatous trichiasis (TT) and/or corneal opacity (CO) due to trachoma in Nigeria, while accounting for the effects of individual risk factors and spatial correlation. In addition, we explore the relative importance of variation in the risk of trichiasis and/or corneal opacity (TT/CO) at different levels. Data from the 2007 National Blindness and Visual Impairment Survey were used for this analysis, which included a nationally representative sample of adults aged 40 years and above. Complete data were available from 304 clusters selected using a multi-stage stratified cluster-random sampling strategy. A...
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Archives of disease in childhood, 2014
The study was conducted to determine whether trained key informants (KI) could identify children ... more The study was conducted to determine whether trained key informants (KI) could identify children with impairments. Trained KI identified children with defined impairments/epilepsy who were then examined by a medical team at a nearby assessment centre (Key Informant Methodology: KIM). A population-based household randomised sample survey was also conducted for comparing the prevalence estimates. Three districts in North Bangladesh. Study population of approximately 258 000 children aged 0-<18 years, within which 3910 children were identified by KI, 94.8% of whom attended assessment camps. In the household survey, 8120 children were examined, of whom 119 were identified with an impairment/epilepsy. Prevalence estimates of severe visual impairment (SVI), moderate/severe hearing impairment (HI), substantial physical impairment (PI) and epilepsy. Overall prevalence estimates of impairments, including presumed HI, showed significant differences comparing KIM (9.0/1000 (95% CI 8.7 to 9....
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BMC public health, 2014
In Nigeria, urbanisation and increasing life expectancy are likely to increase the incidence of n... more In Nigeria, urbanisation and increasing life expectancy are likely to increase the incidence of non-communicable diseases. As the epidemic of diabetes matures, visual loss from diabetic retinopathy (DR) will increase unless mechanisms for early detection and treatment improve, and health systems respond to the growing burden of non-communicable diseases. A nationally-representative population-based sample of 13,591 participants aged ≥40 years selected by multistage-stratified-cluster-random-sampling with probability-proportional-to-size procedures were examined in 305 clusters in Nigeria between January 2005 to June 2007. All were asked about history of diabetes and underwent basic eye examination. Visual acuity (VA) was measured using logMAR E-chart. Participants with VA<6/12 and/or DR detected underwent detailed eye examination including dilated retinal examination and retinal photography. Systematic sampling of 1-in-7 gave a subsample (n=1759) examined in detail regardless of ...
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Otolaryngology - Head and Neck Surgery, 2006
To determine if antibiotics improve recovery following tonsillectomy. Electronic databases Medlin... more To determine if antibiotics improve recovery following tonsillectomy. Electronic databases Medline, Embase, and Cochrane Controlled Trials Register were searched using relevant search terms. Additional trials, if any, were retrieved by searching the references from all identified trials, reviews, correspondences, editorials, and conference proceedings. No language restriction was applied. Systematic review of trials in which antibiotic was administered as a study medication intraoperatively and/or postoperatively, in children or adults undergoing tonsillectomy or adenotonsillectomy. Only randomized, placebo-controlled, double-blind trials attaining preset quality scores were included. Outcomes analyzed: 1) pain, need for analgesia, fever, halitosis, and return to normal diet and activities; 2) secondary hemorrhage using 2 parameters-significant hemorrhage (ie, warranting readmission, blood transfusion, or return to theatre for hemostasis) and total hemorrhage; and 3) adverse events. Five trials met the eligibility criteria. Antibiotics significantly reduced the number of subjects manifesting fever (relative risk [RR]: 0.62, 95% confidence interval [CI]: 0.45, 0.85) and duration of halitosis (-1.94 [-3.57, -0.30] days), and marginally reduced the time taken to resume normal activity (-0.63 [-1.12, -0.14] days), but had no significant effect in reducing pain scores (-0.01 [-0.60, 0.57]) or need for analgesia. Similarly, there was no significant difference in the time taken to resume normal diet or incidence of significant and total hemorrhage, although data was underpowered to detect differences for these outcomes. In the antibiotic group 4 patients developed an adverse reaction (3 cases of rash and 1 case of oropharyngeal candidiasis), while in the control group 1 patient had an adverse reaction (rash). The RR of antibiotic-related adverse events was 2.45 (0.45, 13.31). Antibiotics appear to be effective in reducing some, but not all, morbid outcomes following tonsillectomy, and may increase the risk of adverse events. Further trials are needed to better define the role of antibiotics in facilitating post-tonsillectomy recovery. A-1a.
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Ophthalmic Epidemiology, 2002
Acknowledgments: Thanks are due to Dr. GP Pokharel, Foundation Eye Care Himalaya, who served alon... more Acknowledgments: Thanks are due to Dr. GP Pokharel, Foundation Eye Care Himalaya, who served along with two of the authors (LBE and SRM) on a technical advisory committee that provided assistance with protocol development, project oversight, and data analysis. The authors ...
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Ophthalmic Epidemiology, 2002
To assess the prevalence of visual acuity impairment, blindness, and cataract surgery among older... more To assess the prevalence of visual acuity impairment, blindness, and cataract surgery among older adults in rural southern India. Random selection of village- and urban-based clusters was used to identify a cross-sectional sample of persons 50 years of age or older from the Sivaganga district of Tamil Nadu. Subjects in 25 selected clusters were enumerated through a door-to-door survey and invited to examination sites for measurement of uncorrected, presenting, and best-corrected visual acuity and ocular examination in 1999. The principal cause was identified for eyes with presenting visual acuity worse than 6/18. Quality assurance monitoring of visual acuity measurements took place in five of the study clusters. A total of 5081 persons in 3517 households were enumerated, and 4642 (91.4%) were examined. Thirty-six percent presented with visual acuity worse than 6/18 in the better eye. The prevalence of blindness, based on visual acuity worse than 6/60 in both eyes, was 6.0% (95% confidence interval [CI]: 5.1% to 6.9%) with presenting vision, and 2.5% (95% CI: 1.8% to 3.1%) with best correction. Blindness with presenting visual acuity was associated with older age and illiteracy. Cataract was the principal cause of blindness in one or both eyes in 69.4% of those presenting blind, and uncorrected aphakia and other refractive error affected 35.6% in at least one eye. The prevalence of cataract surgery was 14.7% (95% CI: 13.0% to 16.4%); low surgical coverage among the cataract blind was associated with illiteracy. It appears that much has been done in the prevention of blindness in Sivaganga. Nevertheless, blindness remains an important public health problem, mainly because of cataract and refractive error. Prevention of blindness programs in the area should target these two causes, with special emphasis on the elderly and the illiterate.
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The Journal of Arthroplasty, 2007
Cement pressurization is critical to achieving optimal results in cemented arthroplasty of the hi... more Cement pressurization is critical to achieving optimal results in cemented arthroplasty of the hip. An in vitro experiment using plastic femoral models (10 per group) was undertaken to measure the pressures developed by 3 cementing systems: the Howmedica Mark 1 (Stryker Howmedica, Limerick, Ireland) and DePuy Cemvac retrograde cementation systems (DePuy CMW, Blackpool, UK), and a novel antegrade system consisting of a 60-mL catheter-tipped syringe and a Miller proximal femoral seal (Zimmer Ltd, Swindon, UK). The mean pressure was higher for the syringe system (161.45 +/- 28.9 kPa) than the Mark 1 (103.51 +/- 22.0 kPa) or Cemvac (92.65 +/- 30.7 kPa) systems (P = .0001). In addition, fewer cement mantle defects were seen with the syringe system (1, interquartile range [IQR] 1-2) than the Mark 1 (3, IQR 2-4) or Cemvac (3, IQR 1-3) systems (P = .0256).
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Investigative Ophthalmology & Visual Science, 2009
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Investigative Ophthalmology & Visual Science, 2011
To estimate prevalence and describe causes of functional low vision (FLV) among a nationally repr... more To estimate prevalence and describe causes of functional low vision (FLV) among a nationally representative sample of Nigerian adults, assess socioeconomic risk factors, and estimate the number of adults in Nigeria who might benefit from low vision assessment or rehabilitation services. Multistage, stratified, cluster random sampling with probability proportional to size procedures were used to identify a nationally representative sample of 15,027 persons aged 40 years or older. Distance vision was measured using a reduced logMAR tumbling E-chart. All participants with presenting acuity of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;6/12 in one or both eyes had their corrected acuity measured and underwent detailed clinical examination to determine the cause. FLV was defined as best corrected vision &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;6/18 in the better eye, after excluding those with no light perception in both eyes and those with treatable causes. Analysis took account of the clustered design. In all, 13,591 individuals were examined in 305 clusters (response rate, 89.9%). The crude prevalence of FLV was 3.5% (95% confidence interval, 3.1-3.9%). This was lower than the prevalence of blindness, which was 4.2%. Glaucoma was the most common cause and age the most important risk factor. There are estimated to be approximately 5000 adults with FLV per million population and 340 who are totally blind. Only 9.3% of those with FLV were of working age and literate. These are the first data on the prevalence, causes, and risk factors for FLV from Africa. Results support studies from Asia that the prevalence of FLV is lower than previously thought. Because the majority of adults with FLV in Nigeria live in rural areas and are elderly and not literate, further research is required to assess the nature of the interventions required and who might best deliver them.
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Investigative Ophthalmology & Visual Science, 2014
Investigate prevalence and risk factors for lens opacities among a nationally representative samp... more Investigate prevalence and risk factors for lens opacities among a nationally representative sample of Nigerians aged ≥ 40 years. Across 305 clusters, 13,591 adults were examined. Every seventh participant (n = 1722) was sampled systematically and examined in detail, including lens opacity grading. Lenses were examined at the slit-lamp with pupil dilation and graded using the World Health Organization (WHO) system. Significant opacities were defined as nuclear, cortical, or posterior subcapsular opacity of WHO grade &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;1, or hyper/mature cataract. The category &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;Any Opacity&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; included hyper/mature opacity and aphakia/pseudophakia/couching. Data were collected on sociodemographic and environmental factors, including height and weight. A total of 1631/1722 (95%) in the normative subsample had their lenses graded. Prevalence of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;Any Opacity&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; was 19.8% (95% confidence interval [CI]: 7.9-21.7) the prevalence of all types increased with age, and was higher in females and those not literate. Prevalence of nuclear, cortical, and posterior subcapsular were 8.8% (95% CI: 7.5-10.1); 11.7% (95% CI: 10.0-13.3); and 2.9% (95% CI: 2.1-3.8), respectively. In multivariate analysis, age was an independent risk factor for all types. Nuclear opacity was also associated with female sex (odds ratio [OR] 2.4; 95% CI: 1.5-3.6); lean body mass index (BMI; OR 2.0; 95% CI: 1.1-3.5); and the Igbo ethnic group (OR 4.4; 95% CI: 2.3-8.4). Cortical opacity was also associated with female sex (OR 2.1; 95% CI: 1.5-3.0) and the Yoruba (OR 0.45; 95% CI: 0.3-0.8), but not with BMI. &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;Other Lens Opacities,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; which includes couching, was significantly lower in the Guinea savannah region (OR 0.4; 95% CI: 0.2-0.9), while living in rain forest areas was protective for posterior subcapsular cataracts (OR 0.3; 95% CI: 0.1-0.7). A fifth of Nigerian adults have some degree of lens opacity. Further studies are needed to investigate the role of ethnicity, climate variables, and other risk factors.
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Cornea, 2001
To compare the efficacy and safety of ofloxacin 0.3% ophthalmic solution with ciprofloxacin 0.3% ... more To compare the efficacy and safety of ofloxacin 0.3% ophthalmic solution with ciprofloxacin 0.3% ophthalmic solution in patients with culture-positive bacterial keratitis. Patients with a microbiologic diagnosis of bacterial keratitis were included in this double-masked, parallel-group study and were randomized to treatment with either ofloxacin 0.3% or ciprofloxacin 0.3% ophthalmic solution. One drop of the study medication was instilled during the daytime according to the following schedule: every half-hour on study day 1, every hour on days 2 through 4, and every 2 hours on days 5 through 21. Healing, the primary outcome measure, was defined as complete reepithelialization, accompanied by nonprogression of stromal infiltrate for 2 days. Secondary outcome measures included signs and symptoms of infection. Patients were monitored throughout the study period for any adverse events. A total of 217 patients completed the study: 112 were treated with ofloxacin and 105 were treated with ciprofloxacin. Streptococcus pneumoniae was the most commonly encountered pathogen in all patients. Complete corneal reepithelialization occurred in 85% of those treated with ofloxacin and in 77% of those treated with ciprofloxacin (p = 0.32). The average time to corneal ulcer healing was 13.7 days in those treated with ofloxacin and 14.4 days in those treated with ciprofloxacin. Both treatments were well tolerated with no patient discontinuing the study because of side effects. Ofloxacin 0.3% and ciprofloxacin 0.3% ophthalmic solutions are effective and safe in the treatment of patients with culture-positive bacterial keratitis.
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Complementary Therapies in Medicine, 2003
To study the nature of CAM use in primary care attenders, the involvement of their NHS healthcare... more To study the nature of CAM use in primary care attenders, the involvement of their NHS healthcare professionals in their CAM care and differences in characteristics between CAM users and non-users. Postal questionnaire for primary care attenders and analysis of practice leaflets. Six Scottish GP practices with a range of practice size, CAM provision within practice, deprivation and rurality. Five hundred and fourteen primary care attenders described 1194 incidences of CAM use and gave details about their main therapy. 37% had contact with a practitioner, the rest mainly self-prescribed. The perceived effectiveness of CAM was high. Patients used CAM for a variety of health problems, mainly as an adjuvant to orthodox medicine rather than an alternative. The involvement of the NHS in CAM delivery was small but there is a significant role to ensure patient safety, especially regarding herb-drug interactions. Disclosure rate of CAM use was low. CAM offered options in areas where the provision in the NHS is difficult, including musculo-skeletal and mental health problems. Provision of CAM by the GP is associated with higher CAM use in primary care attenders. It is recommended that healthcare professionals include patients&#39; use of CAM in history taking and clinical decision making.
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The British Journal of Psychiatry, 2006
A higher risk of suicide has been associated with low birth weight in one study, but not yet repl... more A higher risk of suicide has been associated with low birth weight in one study, but not yet replicated. Higher birth order has been associated with self-harm, but not with suicide. To examine the relationship between perinatal circumstances and subsequent young adult suicide in Scotland. Using linked data from the Scottish Morbidity Record and Scottish death records, a birth cohort of 1061830 people was followed-up for a mean of 25.1 years. Data were analysed using Cox regression. Higher maternal parity, younger maternal age (&amp;amp;amp;amp;amp;amp;amp;amp;lt;25 years), non-professional parental occupations and low birth weight (&amp;amp;amp;amp;amp;amp;amp;amp;lt;2500 g) were independently associated with higher suicide risk of offspring as young adults. There was no independent association with gestational age. Our findings provide support for the influence of maternal circumstance and foetal experience on subsequent mental health.
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Papers by Selvaraj Sivasubramaniam