Validation of the Modified Vacs Index in a HIV Infected South Indian Population Initiated on a Naco - Art Regimen: A Cohort Study

Aditya, John Binu (2016) Validation of the Modified Vacs Index in a HIV Infected South Indian Population Initiated on a Naco - Art Regimen: A Cohort Study. Masters thesis, Christian Medical College, Vellore.


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OBJECTIVES : We aimed to validate the Modified VACS index as a prognostic index derived from baseline blood parameters, by predicting patient mortality in HIV patients who had been initiated on a NACO- ART regimen over a 1 year period from 1st June 2012 to 31st May 2013 and compare the predicted mortality with actual mortality using a standardised mortality ratio following a two year period. METHODS : We recruited patients by retrospective analysis from the time period 1st June 2012 to 31st May 2013, who had been initiated on a NACO-ART regimen in the Infectious Diseases (ID) clinic, after a diagnosis of HIV/AIDS. The modified VACS index scores were calculated for the patients in the cohort and the predicted mortality was derived by a logistic regression analysis from these scores. The predicted mortality was compared with actual mortality after following up outcomes following a two year period from 1st June 2013 to 31st May 2015 using a standardised mortality ratio. An ROC curve was also plotted to derive the discriminant function of the modified VACS index. RESULTS : A total of 251 patients initiated on anti-retroviral therapy from 1st June 2012 to 31st May 2013 were recruited in the study. Thirteen deaths were reported at the end of the study period with forty five patients being lost to follow up. Deaths and patients lost to follow up were grouped in an unfavourable outcome group for the purpose of logistic regression analysis. A mean higher score was consistently found in the group with the ‘Unfavourable’ outcomes as compared to the ‘Alive’ group (44.8103 ± 22.46358 as compared to 31.7306 ± 20.39250) which was found to be significant using an independent samples t-test. The C-statistic of the ROC curve was 0.66 which implied a suboptimal discriminant function with a sensitivity of 70%, specificity of 58%, positive predictive value of 35% and negative predictive value of 85.4%. Actual mortality was noted to be lesser than predicted by the modified VACS index (5.18% as compared to 18.5%) which is 28% of the predicted value. The CD-4 count was the only component variable which showed a significant association with outcome (p value = 0.000).

Item Type: Thesis (Masters)
Uncontrolled Keywords: Modified VACS index ; HIV ; prognostic index ; ART.
Subjects: MEDICAL > General Medicine
Depositing User: Subramani R
Date Deposited: 29 Dec 2017 20:25
Last Modified: 29 Dec 2017 20:25

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