Guía de práctica clínica para el diagnóstico y tratamiento de hemofilia en el Seguro Social de Salud del Perú (EsSalud)

Introducción. La hemofilia es un trastorno hemorrágico congénito poco común que requiere un manejo interdisciplinario, complejo, y frecuentemente costoso. El objetivo de la presente guía de práctica clínica (GPC) es proveer recomendaciones clínicas basadas en evidencia para el diagnóstico y tratamiento de hemofilia en el seguro social del Perú (EsSalud). Métodos. Se conformó un grupo elaborador local (GEG-Local) conformado por especialistas en hematología y metodólogos. El GEG-Local formuló ocho preguntas clínicas a ser respondidas por la presente GPC. Se buscaron y seleccionaron GPC de hemofilia que respondieran a las preguntas planteadas y obtuvieran un puntaje mayor a 60% en los dominios uno y tres del instrumento Appraisal of Guidelines for Research and Evaluation II (AGREE-II). Durante el 2016 se realizaron búsquedas bibliográficas en Pubmed, EMBASE y biblioteca Cochrane, para actualizar siete preguntas clínicas de la GPC preseleccionada, y para responder una pregunta de novo. En reuniones de trabajo periódicas, el GEGLocal revisó la evidencia y formuló las recomendaciones y flujogramas usando la metodología Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Finalmente, la GPC fue aprobada con Resolución N° 32-IETSI-ESSALUD-2016. Resultados. La presente GPC abordó ocho preguntas clínicas. En base a dichas preguntas se formularon 22 recomendaciones (tres recomendaciones fuertes y 19 recomendaciones condicionales) y cuatro flujogramas. Conclusión. Este artículo es el resumen de la GPC de EsSalud, en la cual se valoró la evidencia científica disponible sobre diagnóstico y tratamiento de hemofilia.

Systematic review and meta-analysis of secondary prophylaxis for prevention of HIV-related toxoplasmic encephalitis relapse using trimethoprim-sulfamethoxazole

A recent systematic literature and meta-analysis reported relative efficacy of trimethoprim-sulfamethoxazole (TMP-SMX) for the treatment of toxoplasmic encephalitis (TE) in HIV-infected adults. Here, we estimated relapse rates during secondary prophylaxis with TMP-SMX, and further explored differences in relapse rates prior to introduction of highly active antiretroviral therapy (HAART) and the widespread adoption of HAART. A systematic search of PubMed, Embase, and Cochrane Central Register of Controlled Trials yielded 707 studies whereby 663 were excluded after abstract screening, and 38 were excluded after full review leaving 6 studies for extraction. We performed double data extraction with a third-party adjudicator. Study designs varied with only one randomized study, four prospective cohorts and one retrospective cohort. Relapse rates were transformed using the Freeman-Tukey method and pooled using both fixed-effect and random-effects meta-analysis models. The TMP-SMX relapse rate was 16.4% (95% CI = 6.2% to 30.3%) based on random-effects models. When the disaggregated pre-HAART studies (n = 4) were included, the relapse rate was 14.9% (random effects; 95% CI = 3.7% to 31.9%). Analysis of two post-HAART studies indicated a relapse rate of 19.2% (random effects; 95% CI = 2.8% to 45.6%). Comparing the relapse rates between pre- and post-HAART studies were contrary to what might be expected based on known benefits of HAART therapy in this population. Nevertheless, cautious interpretation is necessary considering the heterogeneity of the included studies and a limited number of subjects receiving TMP-SMX reported in the post-HAART era.

[Poor quality of sleep associated with low adherence to highly active antiretroviral therapy in Peruvian patients with HIV/AIDS]

This cross-sectional study analyzed the association between poor quality of sleep and adherence to highly active antiretroviral therapy (HAART) in 389 Peruvian patients with HIV/AIDS. Poor quality of sleep was measured with the Pittsburgh Sleep Quality Index (PSQI) and adherence with the CEAT-VIH (Peruvian adaptation). A Poisson generalized linear model with robust standard errors was used to estimate prevalence ratios and 95%CI. A crude model showed that mild, moderate, and severe poor quality of sleep were associated with inadequate treatment adherence. In the adjusted model for variables associated in the bivariate analysis or variables theoretically associated with adherence, only moderate/severe poor quality of sleep remained associated (PR = 1.34, 95%CI: 1.17-1.54; and PR = 1.34, 95%CI: 1.16-1.57, respectively). The study concluded that moderate/severe poor quality of sleep was independently associated with adherence to HAART. Assessing quality of sleep may be helpful in the comprehensive evaluation of HIV patients.

[Systematic review of the efectiveness of community-based interventions to decrease neonatal mortality]

We evaluated the efficacy/effectiveness of community-based interventions to decrease neonatal mortality. A systematic review of randomized controlled trials, cluster randomized trials and cohort studies of interventions on pregnant women, neonates (up to 28 days after birth) or both was made. Thirty four studies were evaluated (n=844,989): 20 in pregnant women (n=406,172), 6 in neonates (n=24,994), and 8 in both (n=413,823). Risk of bias was generally low. There was heterogeneity among interventions. Interventions such as maternal health education and maternal and neonatal home care were associated to a decrease in neonatal mortality in half of the 6 studies of each group. Supplementation with multiple micronutrients, kangaroo mother care, and maternal supplementation with vitamin A did not decrease neonatal mortality. A few heterogeneous community-based interventions demonstrated a decrease in neonatal mortality.

Cost-effectiveness analysis of pneumococcal conjugate vaccines in preventing pneumonia in Peruvian children

Introduction: Pneumococcal pneumonia (PP) has a high burden of morbimortality in children. Use of pneumococcal conjugate vaccines (PCVs) is an effective preventive measure. After PCV 7-valent (PCV7) withdrawal, PCV 10-valent (PCV10) and PCV 13-valent (PCV13) are the alternatives in Peru. This study aimed to evaluate cost effectiveness of these vaccines in preventing PP in Peruvian children <5 years-old. Methodology: A cost-effectiveness analysis was developed in three phases: a systematic evidence search for calculating effectiveness; a cost analysis for vaccine strategies and outcome management; and an economic model based on decision tree analysis, including deterministic and probabilistic sensitivity analysis using acceptability curves, tornado diagram, and Monte Carlo simulation. A hypothetic 100 vaccinated children/vaccine cohort was built. An incremental cost-effectiveness ratio (ICER) was calculated. Results: The isolation probability for all serotypes in each vaccine was estimated: 38% for PCV7, 41% PCV10, and 17% PCV13. Avoided hospitalization was found to be the best effectiveness model measure. Estimated costs for PCV7, PCV10, and PCV13 cohorts were USD13,761, 11,895, and 12,499, respectively. Costs per avoided hospitalization were USD718 for PCV7, USD333 for PCV10, andUSD 162 for PCV13. At ICER, PCV7 was dominated by the other PCVs. Eliminating PCV7, PCV13 was more cost effective than PCV10 (confirmed in sensitivity analysis). Conclusions: PCV10 and PCV13 are more cost effective than PCV7 in prevention of pneumonia in children <5 years-old in Peru. PCV13 prevents more hospitalizations and is more cost-effective than PCV10. These results should be considered when making decisions about the Peruvian National Inmunizations Schedule.

[Addressing the controversy regarding the association between thimerosal-containing vaccines and autism]

Vaccination is one of the most important public health interventions in the reduction childhood morbidity and mortality. Thimerosal is an organic mercury compound used as preservante in multi-dose vials. Often in Peru, there are waves of controversy about the safety of this type of vaccines, mainly arguing that there is an association between them and autism. As a result of these controversies, there have been some voices asking for laws banning thimerosal-containing vaccines, which would have a large impact in costs and the logistic aspects of the public vaccination programs. The aim of this article is to review the literature for the main controversies about thimerosal in vaccines and its supposed association to autism. We made an historical review about these controversies given the available scientific evidence and the statements from important international organizations. We concluded that the current available evidence do not support an association between thimerosal and childhood neurodevelopmental disorders, such as autism.

Effect of rural-to-urban within-country migration on cardiovascular risk factors in low- and middle-income countries: a systematic review

CONTEXT

Limited information is available of effects of rural-to-urban within-country migration on cardiovascular (CV) risk factors in low- and middle- income countries (LMIC).

OBJECTIVE

A systematic review of studies evaluating these effects was performed with rural and/or urban control groups.

STUDY SELECTION

Two teams of investigators searched observational studies in Medline, Web of Science and Scopus until May 2011. Studies evaluating international migration were excluded.

DATA EXTRACTION

Three investigators extracted the information stratified by gender. Information on 17 known CV risk factors was obtained.

RESULTS

Eighteen studies (n=58,536) were included. Studies were highly heterogeneous with respect to study design, migrant sampling frame, migrant urban exposure and reported CV risk factors. In migrants, commonly reported CV risk factors-systolic and diastolic blood pressure, body mass index, obesity, total cholesterol and low-density lipoprotein-were usually higher or more common than in the rural group and usually lower or less common than in the urban group. This gradient was usually present in both genders. Anthropometric (waist-to-hip ratio, hip/waist circumference, triceps skinfolds) and metabolic (fasting glucose/insulin, insulin resistance) risk factors usually followed the same gradient, but conclusions were weak as information was insufficient. Hypertension, high-density lipoprotein, fibrinogen and C-reactive protein did not follow any pattern.

CONCLUSIONS

In LMIC, most but not all, CV risk factors are higher or more common in migrants than in rural groups but lower or less common than in urban groups. Such gradients may or may not be associated with differential CV events and long-term evaluations are necessary.

Tuberculous meningitis in HIV-infected patients in Brazil: clinical and laboratory characteristics and factors associated with mortality

BACKGROUND

Tuberculous meningitis (TBM) is a growing problem in HIV-infected patients in developing countries, where there is scarce data about this co-infection. Our objectives were to analyze the main features and outcomes of HIV-infected patients with TBM.

METHODS

This was a retrospective study of HIV-infected Brazilian patients admitted consecutively for TBM. All patients had Mycobacterium tuberculosis isolated from the cerebrospinal fluid (CSF). Presenting clinical and laboratory features were studied. Multivariate analysis was used to identify variables associated with death during hospitalization and at 9 months after diagnosis. Survival was estimated using the Kaplan-Meier method.

RESULTS

We included 108 cases (median age 36 years, 72% male). Only 15% had fever, headache, and meningeal signs simultaneously. Forty-eight percent had extrameningeal tuberculosis. The median CD4+ cell count was 65 cells/microl. Among 90 cases, 7% had primary resistance to isoniazid and 9% presented multidrug-resistant strains. The overall mortality during hospitalization was 29% and at 9 months was 41%. Tachycardia and prior highly active antiretroviral therapy (HAART) were associated with 9-month mortality. The 9-month survival rate was 22% (95% confidence interval 12-43%).

CONCLUSIONS

Clinical and laboratory manifestations were unspecific. Disseminated tuberculosis and severe immunosuppression were common. Mortality was high and the 9-month survival rate was low. Tachycardia and prior HAART were associated with death within 9 months of diagnosis.

HTLV-I infection is not associated with a higher risk of death in Peruvian HIV-infected patients

Limited and contradictory information exists regarding the prognosis of HIV/HTLV-I co-infection. Our goal was to estimate the effect of HTLV-I infection on mortality in HIV-infected patients at a HIV reference center in Peru. We studied a retrospective cohort of HIV-infected patients, who were exposed or unexposed to HTLV-I. Exposed patients were Western Blot (WB) positive for both retroviruses. Unexposed patients were WB positive for HIV, and had least one negative EIA for HTLV-I. These were selected among patients who entered our Program immediately before and after each exposed patient, between January 1990 and June 2004. Survival time was considered between the diagnosis of exposure to HTLV-I and death or censoring. Confounding variables were age, gender, baseline HIV clinical stage, baseline CD4+ T cell count, and antiretroviral therapy. We studied 50 exposed, and 100 unexposed patients. Exposed patients had a shorter survival compared to unexposed patients [median survival: 47 months (95% CI: 17-77) vs. 85 months (95% CI: 70-100), unadjusted p = 0.06]. Exposed patients had a higher rate of mortality compared to unexposed patients (HIV/HTLV-I (24/50 [48%]) vs. HIV only (37/100 [37%]), univariable p = 0.2]. HTLV-I exposure was not associated to a higher risk of death in the adjusted analysis: HR: 1.2 (0.4-3.5). AIDS clinical stage and lack of antiretroviral therapy were associated to a higher risk of dying. In conclusions, HTLV-I infection was not associated with a higher risk of death in Peruvian HIV-infected patients. Advanced HIV infection and lack of antiretroviral therapy may explain the excess of mortality in this population.

Prediction of 30-day mortality in older patients with a first acute myocardial infarction

OBJECTIVES

This study sought predictors of mortality in patients aged >or=75 years with a first ST-segment elevation myocardial infarction (STEMI) and evaluated the validity of the GUSTO-I and TIMI risk models.

METHODS

Clinical variables, treatment and mortality data from 433 consecutive patients were collected. Univariable and multivariable logistic regression analyses were applied to identify baseline factors associated with 30-day mortality. Subsequently a model predicting 30-day mortality was created and compared with the performance of the GUSTO-I and TIMI models.

RESULTS

After adjustment, a higher Killip class was the most important predictor (OR 16.1; 95% CI 5.7-45.6). Elevated heart rate, longer time delay to admission, hyperglycemia and older age were also associated with increased risk. Patients with hypercholesterolemia had a significantly lower risk (OR 0.46; 95% CI 0.24-0.86). Discrimination (c-statistic 0.79, 95% CI 0.75-0.84) and calibration (Hosmer-Lemeshow 6, p = 0.5) of our model were good. The GUSTO-I and TIMI risk scores produced adequate discrimination within our dataset (c-statistic 0.76, 95% CI 0.71-0.81, and c-statistic 0.77, 95% CI 0.72-0.82, respectively), but calibration was not satisfactory (HL 21.8, p = 0.005 for GUSTO-I, and HL 20.6, p = 0.008 for TIMI).

CONCLUSIONS

Short-term mortality in elderly patients with a first STEMI depends most importantly on initial clinical and hemodynamic status. The GUSTO-I and TIMI models are insufficiently adequate for providing an exact estimate of 30-day mortality risk.

Is gum chewing useful for ileus after elective colorectal surgery? A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

The evaluation of the usefulness of gum chewing for postoperative ileus has given inconclusive results. We evaluated the efficacy of gum chewing in the treatment of ileus after elective colorectal surgery.

MATERIALS AND METHODS

We performed a meta-analysis of randomized clinical trials comparing the effect of gum chewing+standard treatment vs. standard treatment on ileus after colorectal surgery. MEDLINE, EMBASE, the Cochrane Controlled Trial Register, and the Cochrane Database of Systematic Reviews were searched until August 2008. Primary outcomes were time to first flatus, time to first passage of feces, and length of hospital stay. The mean difference (MD) in hours was calculated with the random effects model to assess the effect of gum chewing on the outcomes.

RESULTS

Six trials including 244 patients were analyzed. Time to first flatus was significantly reduced with gum chewing+standard treatment compared to standard treatment alone (MD -14 h, 95% confidence interval [95%CI] -23.5 to -4.6). Time to first passage of feces was significantly reduced (MD -25 h, 95%CI -42.3 to -7.7), but the length of hospital stay was only marginally reduced (MD -26.2 h, 95%CI -57.5 to 5.2) with gum chewing.

CONCLUSION

In patients with ileus after colonic surgery, gum chewing in addition to standard treatment significantly reduces the time to first flatus and the time to first passage of feces when compared to standard treatment alone. There is also a trend to reduce the length of hospital stay. Gum chewing should be added to the standard treatment of these patients.

A systematic review finds methodological improvements necessary for prognostic models in determining traumatic brain injury outcomes

OBJECTIVES

To describe the modeling techniques used for early prediction of outcome in traumatic brain injury (TBI) and to identify aspects for potential improvements.

STUDY DESIGN AND SETTING

We reviewed key methodological aspects of studies published between 1970 and 2005 that proposed a prognostic model for the Glasgow Outcome Scale of TBI based on admission data.

RESULTS

We included 31 papers. Twenty-four were single-center studies, and 22 reported on fewer than 500 patients. The median of the number of initially considered predictors was eight, and on average five of these were selected for the prognostic model, generally including age, Glasgow Coma Score (or only motor score), and pupillary reactivity. The most common statistical technique was logistic regression with stepwise selection of predictors. Model performance was often quantified by accuracy rate rather than by more appropriate measures such as the area under the receiver-operating characteristic curve. Model validity was addressed in 15 studies, but mostly used a simple split-sample approach, and external validation was performed in only four studies.

CONCLUSION

Although most models agree on the three most important predictors, many were developed on small sample sizes within single centers and hence lack generalizability. Modeling strategies have to be improved, and include external validation.

Prognostic value of cause of injury in traumatic brain injury: results from the IMPACT study

We aimed to describe and quantify the relationship between cause of injury and final outcome following traumatic brain injury (TBI). Individual patient data (N = 8708) from eight therapeutic Phase III randomized clinical trials in moderate or severe TBI, and three TBI surveys were used to investigate the relationship between cause of injury and outcome, as assessed by the Glasgow Outcome Scale (GOS) at 6 months. Proportional odds methodology was applied to quantify the strength of the association and expressed as an odds ratio in a meta-analysis. Heterogeneity across studies was assessed and associations with other predictive factors explored. In a univariate analysis, a strong association between the cause of injury and long-term outcome in moderate to severe TBI patients was observed, with consistent results across the studies. Road traffic accidents (OR 0.66, 95% CI 0.60-0.73), assaults (OR 0.66, 95% CI 0.52-0.84), and injuries sustained during sporting or recreational activities (OR 0.45, 95% CI 0.28-0.71) were all associated with better outcomes than the reference category of falls. Falls were found to be associated with an older age and with a higher incidence of mass lesions. Following adjustment for age in the analysis, the relationship between cause of injury and outcome was lost.

Prognostic value of secondary insults in traumatic brain injury: results from the IMPACT study

We determined the relationship between secondary insults (hypoxia, hypotension, and hypothermia) occurring prior to or on admission to hospital and 6-month outcome after traumatic brain injury (TBI). A meta-analysis of individual patient data, from seven Phase III randomized clinical trials (RCT) in moderate or severe TBI and three TBI population-based series, was performed to model outcome as measured by the Glasgow Outcome Scale (GOS). Proportional odds modeling was used to relate the probability of a poor outcome to hypoxia (N = 5661), hypotension ( N = 6629), and hypothermia ( N = 4195) separately. We additionally analyzed the combined effects of hypoxia and hypotension and performed exploratory analysis of associations with computerized tomography (CT) classification and month of injury. Having a pre-enrollment insult of hypoxia, hypotension or hypothermia is strongly associated with a poorer outcome (odds ratios of 2.1 95% CI [1.7-2.6], 2.7 95% CI [2.1-3.4], and 2.2 95% CI [1.6-3.2], respectively). Patients with both hypoxia and hypotension had poorer outcomes than those with either insult alone. Radiological signs of raised intracranial pressure (CT class III or IV) were more frequent in patients who had sustained hypoxia or hypotension. A significant association was observed between month of injury and hypothermia. The occurrence of secondary insults prior to or on admission to hospital in TBI patients is strongly related to poorer outcome and should therefore be a priority for emergency department personnel.

Predictors of stroke within 30 days in patients with non-ST-segment elevation acute coronary syndromes

AIMS

Stroke is an uncommon but serious complication after non-ST-segment elevation acute coronary syndrome (NSTE-ACS). We aimed to identify predictors of stroke within 30 days in patients who suffered NSTE-ACS.

METHODS AND RESULTS

We pooled data from six trials (n=31 402) that randomized NSTE-ACS patients either to platelet glycoprotein (GP) IIb/IIIa receptor blockers or to placebo/control therapy. Potential predictors of stroke included treatment, demographic, and clinical characteristics. We identified predictors using univariable and multivariable logistic models, and their performance was evaluated with calibration (Hosmer-Lemeshow test) and discrimination (c-statistic). We found 228 (0.7%) all-cause strokes: 155 (0.5%) non-haemorrhagic, 20 (0.06%) haemorrhagic, and 53 without computed tomography (CT) confirmation. Patients with any type of stroke had a 30-day mortality of 25%. Randomization to GP IIb/IIIa receptor blockers was not significantly associated with all-cause stroke [OR (95% CI) 1.08 (0.83-1.41)]. Older age [OR per 10-year increase 1.5 (1.3-1.7)], prior stroke [2.1 (1.4-3.1)], and elevated heart rate [per 10-beat increase 1.1 (1.0-1.2)] were the strongest predictors of 30-day all-cause stroke. Similar predictors were found for non-haemorrhagic and haemorrhagic strokes. Smoking, previous myocardial infarction, diabetes, and hypertension were not independent predictors of all-cause stroke. The multivariable model to predict all-cause stroke was well calibrated, but its discrimination was only moderate [c-statistic 0.69 (0.65-0.72)].

CONCLUSION

Stroke is a rare complication occurring early after NSTE-ACS, but is associated with high mortality. We found no evidence that GP IIb/IIIa receptor blockers increase stroke risks. A few clinical characteristics predicted higher stroke risks. Thus, incident strokes in NSTE-ACS patients remain largely unexplained.

Effects of platelet glycoprotein IIb/IIIa receptor blockers in non-ST segment elevation acute coronary syndromes: benefit and harm in different age subgroups

OBJECTIVE

To investigate whether the beneficial and harmful effects of platelet glycoprotein IIb/IIIa receptor blockers in non-ST elevation acute coronary syndromes (NSTE-ACS) depend on age.

METHODS

A meta-analysis of six trials of platelet glycoprotein IIb/IIIa receptor blockers in patients with NSTE-ACS (PRISM, PRISM-PLUS, PARAGON-A, PURSUIT, PARAGON-B, GUSTO IV-ACS; n = 31 402) was performed. We applied multivariable logistic regression analyses to evaluate the drug effects on death or non-fatal myocardial infarction at 30 days, and on major bleeding, by age subgroups (<60, 60-69, 70-79, > or =80 years). We quantified the reduction of death or myocardial infarction as the number needed to treat (NNT), and the increase of major bleeding as the number needed to harm (NNH).

RESULTS

Subgroups had 11 155 (35%), 9727 (31%), 8468 (27%) and 2049 (7%) patients, respectively. The relative benefit of platelet glycoprotein IIb/IIIa receptor blockers did not differ significantly (p = 0.5) between age subgroups (OR (95% CI) for death or myocardial infarction: 0.86 (0.74 to 0.99), 0.90 (0.80 to 1.02), 0.97 (0.86 to 1.10), 0.90 (0.73 to 1.16); overall 0.91 (0.86 to 0.99). ORs for major bleeding were 1.9 (1.3 to 2.8), 1.9 (1.4 to 2.7), 1.6 (1.2 to 2.1) and 2.5 (1.5-4.1). Overall NNT was 105, and overall NNH was 90. The oldest patients had larger absolute increases in major bleeding, but also had the largest absolute reductions of death or myocardial infarction. Patients > or =80 years had half of the NNT and a third of the NNH of patients <60 years.

CONCLUSIONS

In patients with NSTE-ACS, the relative reduction of death or non-fatal myocardial infarction with platelet glycoprotein IIb/IIIa receptor blockers was independent of patient age. Larger absolute outcome reductions were seen in older patients, but with a higher risk of major bleeding. Close monitoring of these patients is warranted.

Adjustment for Strong Predictors of Outcome in Traumatic Brain Injury Trials: 25% Reduction in Sample Size Requirements in the IMPACT Study

The aim of this study was to quantify the potential reduction in sample size that can be achieved by adjustment for predictors of outcome in traumatic brain injury (TBI) trials. We used individual patient data from seven therapeutic phase III randomized clinical trials (RCTs; n = 6166) in moderate or severe TBI, and three TBI surveys (n = 2238). The primary outcome was the dichotomized Glasgow Outcome Scale at 6 months (favorable/unfavorable). Baseline predictors of outcome considered were age, motor score, pupillary reactivity, computed tomography (CT) classification, traumatic subarachnoid hemorrhage, hypoxia, hypotension, glycemia, and hemoglobin. We calculated the potential sample size reduction obtained by adjustment of a hypothetical treatment effect for one to seven predictors with logistic regression models. The distribution of predictors was more heterogeneous in surveys than in trials. Adjustment of the treatment effect for the strongest predictors (age, motor score, and pupillary reactivity) yielded a reduction in sample size of 16-23% in RCTs and 28-35% in surveys. Adjustment for seven predictors yielded a reduction of about 25% in most studies: 20-28% in RCTs and 32-39% in surveys. A major reduction in sample size can be obtained with covariate adjustment in TBI trials. Covariate adjustment for strong predictors should be incorporated in the analysis of future TBI trials.

Subgroup analyses in therapeutic cardiovascular clinical trials: are most of them misleading?

BACKGROUND

Treatment decisions in clinical cardiology are directed by results from randomized clinical trials (RCTs). We studied the appropriateness of the use and interpretation of subgroup analysis in current therapeutic cardiovascular RCTs.

METHODS

We reviewed main reports of phase 3 cardiovascular RCTs with at least 100 patients, published in 2002 and 2004, and from major journals (Circulation, J Am Coll Cardiol, Am Heart J, Am J Cardiol, N Engl J Med, Lancet, JAMA, BMJ, Ann Intern Med). Information on subgroups included prespecification, number, interaction test use, significant subgroups found, and emphasis on findings. We examined appropriateness of reporting and differences according to sample size, overall trial result, and CONSORT adoption.

RESULTS

We selected 63 RCTs, with a median of 496 (range 100-15,245) patients. Thirty-nine RCTs were reported with subgroup analyses and 26 with > 5 subgroups. No trial was specifically powered to detect subgroup effects, and only 14 RCTs were reported with fully prespecified subgroups. Only 11 RCTs were reported with interaction tests. Furthermore, 21 RCTs were reported with claims of significant subgroups and 15 with equal or more emphasis to subgroups than to the overall results. Subgroup analyses in large RCTs (> 500 patients) were reported more often than in small ones (24/30 vs 15/33, P = .005). No differences were found according to overall result (positive/negative) or CONSORT adoption.

CONCLUSIONS

Subgroup analyses in recent cardiovascular RCTs were reported with several shortcomings, including a lack of prespecification and testing of a large number of subgroups without the use of the statistically appropriate test for interaction. Reporting of subgroup analysis needs to be substantially improved because emphasis on these secondary results may mislead treatment decisions.

High proportion of T-cell systemic non-Hodgkin lymphoma in HIV-infected patients in Lima, Peru

OBJECTIVE

Few reports have described the clinical and pathologic characteristics of HIV-related systemic non-Hodgkin lymphoma (sNHL) in developing countries. We aimed to determine these characteristics from a national HIV reference center in Peru and to evaluate factors associated with survival.

METHODS

A retrospective/prospective study of patients with HIV-related sNHL from the Guillermo Almenara General Hospital in Lima, Peru between 1993 and 2004. Clinical characteristics at diagnosis included age, gender, risk behavior, previous AIDS diagnosis, opportunistic diseases, previous highly active antiretroviral therapy, Karnofsky score, origin, clinical stage and B-cell symptoms of sNHL, and CD4 cell count. Cases of sNHL were classified according to the criteria of the World Health Organization.

RESULTS

Thirty-three cases were identified (26 male, age range: 38 +/- 10 years). Ten patients (30%) had a prior history of AIDS, 14 (42%) had a Karnofsky score of <or=70, and 18 (56%) had clinical stage IV sNHL. The CD4 cell count median value was 111 cells/microL (n = 25). Twenty-four cases (73%) were B-cell sNHL, and 9 cases (27%) were T-cell sNHL, both from peripheral cells. Nineteen cases of sNHL were extranodal: 15 of B-cell origin and 4 of T-cell origin. Eighteen cases of B-cell sNHL had diffuse large cell histologic findings, and all cases of T-cell sNHL were unspecified. Although there were no significant differences in clinical characteristics between phenotypes, patients with T-cell sNHL had less aggressive disease and a better survival rate.

CONCLUSIONS

A high proportion of T-cell sNHL cases was found at an HIV reference center in Peru. Clinical characteristics were similar between B-cell and T-cell lymphoma patients. T-cell lymphoma was less aggressive, and patients with T-cell lymphoma had a better survival rate than those with B-cell lymphoma.

Randomized controlled trials with time-to-event outcomes: how much does prespecified covariate adjustment increase power?

PURPOSE

We evaluated the effects of various strategies of covariate adjustment on type I error, power, and potential reduction in sample size in randomized controlled trials (RCTs) with time-to-event outcomes.

METHODS

We used Cox models in simulated data sets with different treatment effects (hazard ratios [HRs] = 1, 1.4, and 1.7), covariate effects (HRs = 1, 2, and 5), covariate prevalences (10% and 50%), and censoring levels (no, low, and high). Treatment and a single covariate were dichotomous. We examined the sample size that gives the same power as an unadjusted analysis for three strategies: prespecified, significant predictive, and significant imbalance.

RESULTS

Type I error generally was at the nominal level. The power to detect a true treatment effect was greater with adjusted than unadjusted analyses, especially with prespecified and significant-predictive strategies. Potential reductions in sample size with a covariate HR between 2 and 5 were between 15% and 44% (covariate prevalence 50%) and between 4% and 12% (covariate prevalence 10%). The significant-imbalance strategy yielded small reductions. The reduction was greater with stronger covariate effects, but was independent of treatment effect, sample size, and censoring level.

CONCLUSIONS

Adjustment for one predictive baseline characteristic yields greater power to detect a true treatment effect than unadjusted analysis, without inflation of type I error and with potentially moderate reductions in sample size. Analysis of RCTs with time-to-event outcomes should adjust for predictive covariates.

Cerebral tuberculomas in AIDS patients: a forgotten diagnosis?

The human immunodeficiency virus (HIV) infection epidemics increased the prevalence, multi-drug resistance and disseminated forms of tuberculosis. The central nervous system (CNS) tuberculosis has high mortality and morbidity, and it is usually divided into diffuse (meningitis) and localized (tuberculoma and abscess) forms. We report three cases of cerebral tuberculomas in AIDS patients: one with definitive diagnosis, confirmed with histopathology, and two with probable diagnosis, based on clinical information, radiological images, Mycobaterium tuberculosis isolation out of the CNS and adequate response to antituberculous treatment. Further, we discuss diagnostic, therapeutic and prognostic issues of tuberculomas, with emphasis in the distinction from cerebral tuberculous abscesses. Despite of their infrequent presentation, tuberculomas should be considered in the differential diagnosis of cerebral expansive lesions in patients with AIDS.

Covariate adjustment in randomized controlled trials with dichotomous outcomes increases statistical power and reduces sample size requirements

OBJECTIVE

Randomized controlled trials (RCTs) with dichotomous outcomes may be analyzed with or without adjustment for baseline characteristics (covariates). We studied type I error, power, and potential reduction in sample size with several covariate adjustment strategies.

STUDY DESIGN AND SETTING

Logistic regression analysis was applied to simulated data sets (n=360) with different treatment effects, covariate effects, outcome incidences, and covariate prevalences. Treatment effects were estimated with or without adjustment for a single dichotomous covariate. Strategies included always adjusting for the covariate ("prespecified"), or only when the covariate was predictive or imbalanced.

RESULTS

We found that the type I error was generally at the nominal level. The power was highest with prespecified adjustment. The potential reduction in sample size was higher with stronger covariate effects (from 3 to 46%, at 50% outcome incidence and covariate prevalence) and independent of the treatment effect. At lower outcome incidences and/or covariate prevalences, the reduction was lower.

CONCLUSION

We conclude that adjustment for a predictive baseline characteristic may lead to a potentially important increase in power of analyses of treatment effect. Adjusted analysis should, hence, be considered more often for RCTs with dichotomous outcomes.