Medicine (RMH) - Research Publications
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ItemPrognostic Indicators in Pediatric Clinically Isolated Syndrome(WILEY, 2017-05)OBJECTIVE: To assess prognostic factors for a second clinical attack and a first disability-worsening event in pediatric clinically isolated syndrome (pCIS) suggestive of multiple sclerosis (MS) patients. METHODS: A cohort of 770 pCIS patients was followed up for at least 10 years. Cox proportional hazard models and Recursive Partitioning and Amalgamation (RECPAM) tree-regression were used to analyze data. RESULTS: In pCIS, female sex and a multifocal onset were risk factors for a second clinical attack (hazard ratio [HR], 95% confidence interval [CI] = 1.28, 1.06-1.55; 1.42, 1.10-1.84, respectively), whereas disease-modifying drug (DMD) exposure reduced this risk (HR, 95% CI = 0.75, 0.60-0.95). After pediatric onset MS (POMS) diagnosis, age at onset younger than 15 years and DMD exposure decreased the risk of a first Expanded Disability Status Scale (EDSS)-worsening event (HR, 95% CI = 0.59, 0.42-0.83; 0.75, 0.71-0.80, respectively), whereas the occurrence of relapse increased this risk (HR, 95% CI = 5.08, 3.46-7.46). An exploratory RECPAM analysis highlighted a significantly higher incidence of a first EDSS-worsening event in patients with multifocal or isolated spinal cord or optic neuritis involvement at onset in comparison to those with an isolated supratentorial or brainstem syndrome. A Cox regression model including RECPAM classes confirmed DMD exposure as the most protective factor against EDSS-worsening events and relapses as the most important risk factor for attaining EDSS worsening. INTERPRETATION: This work represents a step forward in identifying predictors of unfavorable course in pCIS and POMS and supports a protective effect of early DMD treatment in preventing MS development and disability accumulation in this population. Ann Neurol 2017;81:729-739.
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ItemPredictors of Long-Term Disability Accrual in Relapse-Onset Multiple Sclerosis(WILEY, 2016-07)OBJECTIVE: To identify predictors of 10-year Expanded Disability Status Scale (EDSS) change after treatment initiation in patients with relapse-onset multiple sclerosis. METHODS: Using data obtained from MSBase, we defined baseline as the date of first injectable therapy initiation. Patients need only have remained on injectable therapy for 1 day and were monitored on any approved disease-modifying therapy, or no therapy thereafter. Median EDSS score changes over a 10-year period were determined. Predictors of EDSS change were then assessed using median quantile regression analysis. Sensitivity analyses were further performed. RESULTS: We identified 2,466 patients followed up for at least 10 years reporting post-baseline disability scores. Patients were treated an average 83% of their follow-up time. EDSS scores increased by a median 1 point (interquartile range = 0-2) at 10 years post-baseline. Annualized relapse rate was highly predictive of increases in median EDSS over 10 years (coeff = 1.14, p = 1.9 × 10(-22) ). On-therapy relapses carried greater burden than off-therapy relapses. Cumulative treatment exposure was independently associated with lower EDSS at 10 years (coeff = -0.86, p = 1.3 × 10(-9) ). Furthermore, pregnancies were also independently associated with lower EDSS scores over the 10-year observation period (coeff = -0.36, p = 0.009). INTERPRETATION: We provide evidence of long-term treatment benefit in a large registry cohort, and provide evidence of long-term protective effects of pregnancy against disability accrual. We demonstrate that high annualized relapse rate, particularly on-treatment relapse, is an indicator of poor prognosis. Ann Neurol 2016;80:89-100.
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ItemRisk of early relapse following the switch from injectables to oral agents for multiple sclerosis(WILEY, 2016-04)BACKGROUND AND PURPOSE: Early relapse outcomes in long-term stable patients switching from interferon β/glatiramer acetate (IFNβ/GA) to oral therapy are unknown. OBJECTIVE: The objective of this study was to compare early relapse and progression in multiple sclerosis (MS) patients switching to oral therapy following a period of stable disease on IFNβ/GA, relative to a propensity-matched comparator of patients remaining on IFNβ/GA. METHODS: The MSBase cohort study is a global, longitudinal registry for MS. Time to first 6-month relapse in previously stable MS patients switching from platform injectables ('switchers') to oral agents were compared with propensity-matched patients remaining on IFNβ/GA ('stayers') using a Cox marginal model. RESULTS: Three-hundred and ninety-six switchers were successfully matched to 396 stayers on a 1:1 basis. There was no difference in the proportion of patients recording at least one relapse in the first 1-6 months by treatment arm (7.3% switchers, 6.6% stayers; P = 0.675). The mean annualized relapse rate (P = 0.493) and the rate of first 6-month relapse by treatment arm (hazard ratio 1.22, 95% confidence interval 0.70, 2.11) were also comparable. There was no difference in the rate of disability progression by treatment arm (hazard ratio 1.43, 95% confidence interval 0.63, 3.26). CONCLUSION: This is the first study to compare early relapse switch probability in the period immediately following switch to oral treatment in a population previously stable on injectable therapy. There was no evidence of disease reactivation within the first 6 months of switching to oral therapy.
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ItemIntrahousehold Transmission of Pandemic (H1N1) 2009 Virus, Victoria, Australia(CENTERS DISEASE CONTROL & PREVENTION, 2011-09)To examine intrahousehold secondary transmission of pandemic (H1N1) 2009 virus in households in Victoria, Australia, we conducted a retrospective cross-sectional study in late 2009. We randomly selected case-patients reported during May-June 2009 and their household contacts. Information collected included household characteristics, use of prevention and control measures, and signs and symptoms. Secondary cases were defined as influenza-like illness in household contacts within the specified period. Secondary transmission was identified for 18 of 122 susceptible household contacts. To identify independent predictors of secondary transmission, we developed a model. Risk factors were concurrent quarantine with the household index case-patient, and a protective factor was antiviral prophylaxis. These findings show that timely provision of antiviral prophylaxis to household contacts, particularly when household members are concurrently quarantined during implementation of pandemic management strategies, delays or contains community transmission of pandemic (H1N1) 2009 virus.
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ItemPersistence on therapy and propensity matched outcome comparison of two subcutaneous interferon beta 1a dosages for multiple sclerosis.(Public Library of Science (PLoS), 2013)OBJECTIVES: To compare treatment persistence between two dosages of interferon β-1a in a large observational multiple sclerosis registry and assess disease outcomes of first line MS treatment at these dosages using propensity scoring to adjust for baseline imbalance in disease characteristics. METHODS: Treatment discontinuations were evaluated in all patients within the MSBase registry who commenced interferon β-1a SC thrice weekly (n = 4678). Furthermore, we assessed 2-year clinical outcomes in 1220 patients treated with interferon β-1a in either dosage (22 µg or 44 µg) as their first disease modifying agent, matched on propensity score calculated from pre-treatment demographic and clinical variables. A subgroup analysis was performed on 456 matched patients who also had baseline MRI variables recorded. RESULTS: Overall, 4054 treatment discontinuations were recorded in 3059 patients. The patients receiving the lower interferon dosage were more likely to discontinue treatment than those with the higher dosage (25% vs. 20% annual probability of discontinuation, respectively). This was seen in discontinuations with reasons recorded as "lack of efficacy" (3.3% vs. 1.7%), "scheduled stop" (2.2% vs. 1.3%) or without the reason recorded (16.7% vs. 13.3% annual discontinuation rate, 22 µg vs. 44 µg dosage, respectively). Propensity score was determined by treating centre and disability (score without MRI parameters) or centre, sex and number of contrast-enhancing lesions (score including MRI parameters). No differences in clinical outcomes at two years (relapse rate, time relapse-free and disability) were observed between the matched patients treated with either of the interferon dosages. CONCLUSIONS: Treatment discontinuations were more common in interferon β-1a 22 µg SC thrice weekly. However, 2-year clinical outcomes did not differ between patients receiving the different dosages, thus replicating in a registry dataset derived from "real-world" database the results of the pivotal randomised trial. Propensity score matching effectively minimised baseline covariate imbalance between two directly compared sub-populations from a large observational registry.
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ItemImpact of Hiv-Associated Conditions on Mortality in People Commencing Anti-Retroviral Therapy in Resource Limited Settings(PUBLIC LIBRARY SCIENCE, 2013-07-23)OBJECTIVES: To identify associations between specific WHO stage 3 and 4 conditions diagnosed after ART initiation and all cause mortality for patients in resource-limited settings (RLS). DESIGN, SETTING: Analysis of routine program data collected prospectively from 25 programs in eight countries between 2002 and 2010. SUBJECTS, PARTICIPANTS: 36,664 study participants with median ART follow-up of 1.26 years (IQR 0.55-2.27). OUTCOME MEASURES: Using a proportional hazards model we identified factors associated with mortality, including the occurrence of specific WHO clinical stage 3 and 4 conditions during the 6-months following ART initiation. RESULTS: There were 2922 deaths during follow-up (8.0%). The crude mortality rate was 5.41 deaths per 100 person-years (95% CI: 5.21-5.61). The diagnosis of any WHO stage 3 or 4 condition during the first 6 months of ART was associated with increased mortality (HR: 2.21; 95% CI: 1.97-2.47). After adjustment for age, sex, region and pre-ART CD4 count, a diagnosis of extrapulmonary cryptococcosis (aHR: 3.54; 95% CI: 2.74-4.56), HIV wasting syndrome (aHR: 2.92; 95%CI: 2.21 -3.85), non-tuberculous mycobacterial infection (aHR: 2.43; 95% CI: 1.80-3.28) and Pneumocystis pneumonia (aHR: 2.17; 95% CI 1.80-3.28) were associated with the greatest increased mortality. Cerebral toxoplasmosis, pulmonary and extra-pulmonary tuberculosis, Kaposi's sarcoma and oral and oesophageal candidiasis were associated with increased mortality, though at lower rates. CONCLUSIONS: A diagnosis of certain WHO stage 3 and 4 conditions is associated with an increased risk of mortality in those initiating ART in RLS. This information will assist initiatives to reduce excess mortality, including prioritization of resources for diagnostics, therapeutic interventions and research.
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ItemIncidence of WHO Stage 3 and 4 Conditions following Initiation of Anti-Retroviral Therapy in Resource Limited Settings(PUBLIC LIBRARY SCIENCE, 2012-12-20)OBJECTIVES: To determine the incidence of WHO clinical stage 3 and 4 conditions during early anti-retroviral therapy (ART) in resource limited settings (RLS). DESIGN/SETTING: A descriptive analysis of routine program data collected prospectively from 25 Médecins Sans Frontières supported HIV treatment programs in eight countries between 2002 and 2010. SUBJECTS/PARTICIPANTS: 35,349 study participants with median follow-up on ART of 1.33 years (IQR 0.51-2.41). OUTCOME MEASURES: Incidence in 100 person-years of WHO stage 3 or 4 conditions during 5 periods after ART initiation. Diagnoses of conditions were made according to WHO criteria and relied upon clinical assessments supported by basic laboratory investigations. RESULTS: The incidence of any WHO clinical stage 3 or 4 condition over 3 years was 40.02 per 100 person-years (31.77 for stage 3 and 8.25 for stage 4). The incidence of stage 3 and 4 conditions fell by over 97% between months 0-3 and months 25-36 (77.81 to 2.40 for stage 3 and 28.70 to 0.64 for stage 4). During months 0-3 pulmonary tuberculosis was the most common condition diagnosed in adults (incidence 22.24 per 100 person-years) and children aged 5-14 years (25.76) and oral candidiasis was the most common in children <5 years (25.79). Overall incidences were higher in Africa compared with Asia (43.98 versus 12.97 for stage 3 and 8.98 versus 7.05 for stage 4 conditions, p<0.001). Pulmonary tuberculosis, weight loss, oral and oesophageal candidiasis, chronic diarrhoea, HIV wasting syndrome and severe bacterial infections were more common in Africa. Extra-pulmonary tuberculosis, non-tuberculous mycobacterial infection, cryptococcosis, penicilliosis and toxoplasmosis were more common in Asia. CONCLUSIONS: The incidence of WHO stage 3 and 4 conditions during the early period after ART initiation in RLS is high, but greatly reduces over time. This is likely due to both the benefits of ART and deaths of the sickest patients occurring shortly after ART initiation. Access to appropriate disease prevention tools prior to ART, and early initiation of ART, are important for their prevention.
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ItemPredictors of Raised Viral Load during Antiretroviral Therapy in Patients with and without Prior Antiretroviral Use: A Cross-Sectional Study(PUBLIC LIBRARY SCIENCE, 2013-08-14)OBJECTIVES: In Lagos, Nigeria, Médecins Sans Frontières (MSF) and the Ministry of Health (MoH) commenced free antiretroviral treatment (ART) in a hospital-based clinic. We performed a cross-sectional study to compare factors associated with raised viral load between patients with ("experienced") and without ("naïve") prior antiretroviral (ARV) exposure at commencement of ART at the clinic. We also examined factors influencing ARV adherence in experienced patients prior to clinic entry. METHODS: We included adult patients receiving ART from MSF who answered a questionnaire about previous antiretroviral use. Multivariate logistic regression was used to estimate odds ratios (OR) for raised viral load (≥1000 copies/mL). RESULTS: 1246 (96%) patients answered: 1075 (86%) reported no, and 171 (14%) some, prior ARV exposure. ARV-naïve patients were more immunosuppressed at baseline: 65% vs 37% (p<0.001) had CD4<200; 17% vs 9% (p = 0.013) were WHO stage 4. Proportionately more experienced than naïve patients had raised viral loads (20% vs 9%, p<0.001) on ART in the MSF/MoH clinic. Raised viral load was associated with prior ARV experience (adjusted OR = 3.74, 95%CI 2.09-6.70, p<0.001) and complete interruption of current ART (adjusted OR = 3.71, 95%CI 2.06-6.68, p<0.001). Higher CD4 at time of VL and a higher self-rated score of recent adherence were associated with lower OR of a raised viral load. Among experienced patients who missed pills before joining MSF/MoH, most common reasons were because ARVS were not affordable (58%) or available (33%), with raised viral load associated with being unsure how to take them (OR = 3.16, 95%CI 1.10-9.12, p = 0.033). CONCLUSIONS: Patients previously exposed to ARVs had increased OR of raised viral load. The cost and availability of ARVs were common reasons for missing ARVs before joining the MSF/MoH clinic, and inadequate patient knowledge was associated with raised viral load.
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ItemRisk factors for unstructured treatment interruptions and association with survival in low to middle income countries(BIOMED CENTRAL LTD, 2016-07-11)BACKGROUND: Antiretroviral therapy (ART) treatment interruptions lead to poor clinical outcomes with unplanned or unstructured TIs (uTIs) likely to be underreported. This study describes; uTIs, their risk factors and association with survival. METHODS: Analysis of ART programmatic data from 11 countries across Asia and Africa between 2003 and 2013 where an uTI was defined as a ≥90-day patient initiated break from ART calculated from the last day the previous ART prescription would have run out until the date of the next ART prescription. Factors predicting uTI were assessed with a conditional risk-set multiple failure time-to-event model to account for repeated events per subject. Association between uTI and mortality was assessed using Cox proportional hazards, with a competing risks extension to test for the influence of lost to follow-up (LTFU). RESULTS: 40,632 patients were included from 11 countries across 33 sites (17 Africa, 16 Asia). Median duration of follow-up was 1.61 years (IQR 0.54-3.31 years), 3386 (8.3 %) patients died, and 3453 (8.5 %) were LTFU. There were 14,817 uTIs, with 10,162 (25 %) patients having more than one uTI. In the adjusted model males were at lower risk of uTI (aHR 0.94, p < 0.01, and age 20-59 was protective compared to <20 years (20-39 years aHR 0.87, p < 0.01; 40-59 years aHR 0.86, p < 0.01). Preserved immune function, as measured by higher CD4 cell count, was associated with a reduced rate of uTI compared to CD4 <200 cells/μL (CD4 200-350 cells/μL aHR 0.89, p < 0.01; CD4 >350 cells/μL aHR 0.87, p < 0.01), whereas advanced clinical disease was associated with increased uTI rate (WHO stage 3 aHR 1.10, p < 0.01; WHO stage 4 aHR 1.21, p < 0.01). There was no relationship between uTI and mortality after adjusting for disease status and considering LTFU as a competing risk. CONCLUSIONS: uTIs were frequent in people in ART programs in low-middle income countries and associated with younger age, female gender and advanced HIV. uTI did not predict survival when loss to follow-up was considered a competing risk. Further evaluation of uTI predictors and interventions to reduce their occurrence is warranted.
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ItemHigh Rates of Hepatitis C Virus Reinfection and Spontaneous Clearance of Reinfection in People Who Inject Drugs: A Prospective Cohort Study(PUBLIC LIBRARY SCIENCE, 2013-11-07)UNLABELLED: Hepatitis C virus reinfection and spontaneous clearance of reinfection were examined in a highly characterised cohort of 188 people who inject drugs over a five-year period. Nine confirmed reinfections and 17 possible reinfections were identified (confirmed reinfections were those genetically distinct from the previous infection and possible reinfections were used to define instances where genetic differences between infections could not be assessed due to lack of availability of hepatitis C virus sequence data). The incidence of confirmed reinfection was 28.8 per 100 person-years (PY), 95%CI: 15.0-55.4; the combined incidence of confirmed and possible reinfection was 24.6 per 100 PY (95%CI: 16.8-36.1). The hazard of hepatitis C reinfection was approximately double that of primary hepatitis C infection; it did not reach statistical significance in confirmed reinfections alone (hazard ratio [HR]: 2.45, 95%CI: 0.87-6.86, p=0.089), but did in confirmed and possible hepatitis C reinfections combined (HR: 1.93, 95%CI: 1.01-3.69, p=0.047) and after adjustment for the number of recent injecting partners and duration of injecting. In multivariable analysis, shorter duration of injection (HR: 0.91; 95%CI: 0.83-0.98; p=0.019) and multiple recent injecting partners (HR: 3.12; 95%CI: 1.08-9.00, p=0.035) were independent predictors of possible and confirmed reinfection. Time to spontaneous clearance was shorter in confirmed reinfection (HR: 5.34, 95%CI: 1.67-17.03, p=0.005) and confirmed and possible reinfection (HR: 3.10, 95%CI: 1.10-8.76, p-value=0.033) than primary infection. Nonetheless, 50% of confirmed reinfections and 41% of confirmed or possible reinfections did not spontaneously clear. CONCLUSIONS: Hepatitis C reinfection and spontaneous clearance of hepatitis C reinfection were observed at high rates, suggesting partial acquired natural immunity to hepatitis C virus. Public health campaigns about the risks of hepatitis C reinfection are required.