Simultaneous Treatment of Missing Data and Measurement Error in HIV Research Using Multiple Overimputation.

BACKGROUND: Both CD4 count and viral load in HIV-infected persons are measured with error. There is no clear guidance on how to deal with this measurement error in the presence of missing data. METHODS: We used multiple overimputation, a method recently developed in the political sciences, to account for both measurement error and missing data in CD4 count and viral load measurements from four South African cohorts of a Southern African HIV cohort collaboration. Our knowledge about the measurement error of ln CD4 and log10 viral load is part of an imputation model that imputes both missing and mismeasured data. In an illustrative example, we estimate the association of CD4 count and viral load with the hazard of death among patients on highly active antiretroviral therapy by means of a Cox model. Simulation studies evaluate the extent to which multiple overimputation is able to reduce bias in survival analyses. RESULTS: Multiple overimputation emphasizes more strongly the influence of having high baseline CD4 counts compared to both a complete case analysis and multiple imputation (hazard ratio for >200 cells/mm vs. <25 cells/mm: 0.21 [95% confidence interval: 0.18, 0.24] vs. 0.38 [0.29, 0.48], and 0.29 [0.25, 0.34], respectively). Similar results are obtained when varying assumptions about measurement error, when using p-splines, and when evaluating time-updated CD4 count in a longitudinal analysis. The estimates of the association with viral load are slightly more attenuated when using multiple imputation instead of multiple overimputation. Our simulation studies suggest that multiple overimputation is able to reduce bias and mean squared error in survival analyses. CONCLUSIONS: Multiple overimputation, which can be used with existing software, offers a convenient approach to account for both missing and mismeasured data in HIV research.

Clinical Evidence Informing Treatment Guidelines on Repurposed Drugs for Hospitalized Patients During the Early COVID-19 Pandemic: Corticosteroids, Anticoagulants, (Hydroxy)chloroquine.

INTRODUCTION: In early 2020, the coronavirus disease 2019 (COVID-19) pandemic spread worldwide, overwhelming hospitals with severely ill patients and posing the urgent need for clinical evidence to guide patient care. First treatment options available were repurposed drugs to fight inflammation, coagulopathy, and viral replication. A vast number of clinical studies were launched globally to test their efficacy and safety. Our analysis describes the development of global evidence on repurposed drugs, in particular corticosteroids, anticoagulants, and (hydroxy)chloroquine in hospitalized COVID-19 patients based on different study types. We track the incorporation of clinical data in international and national treatment guidelines and identify factors that characterize studies and analyses with the greatest impact on treatment recommendations. METHODS: A literature search in MEDLINE was conducted to assess the clinical evidence on treatment with corticosteroids, anticoagulants, and (hydroxy)chloroquine in hospitalized COVID-19 patients during the first year of the pandemic. Adoption of the evidence from this clinical data in treatment guidelines of the World Health Organization (WHO), Germany, and United States (US) was evaluated over time. RESULTS: We identified 106 studies on corticosteroids, 141 studies on anticoagulants, and 115 studies on (hydroxy)chloroquine. Most studies were retrospective cohort studies; some were randomized clinical trials (RCTs), and a few were platform trials. These studies were compared to studies directly and indirectly referred to in WHO (7 versions), German (5 versions), and US (21 versions) guidelines. We found that initially large, well-adjusted, mainly retrospective cohort studies and ultimately large platform trials or coordinated meta-analyses of RCTs provided best available clinical evidence supporting treatment recommendations. DISCUSSION: Particularly early in the pandemic, evidence for the efficacy and safety of repurposed drugs was of low quality, since time and scientific rigor seemed to be competing factors. Pandemic preparedness, coordinated efforts, and combined analyses were crucial to generating timely and robust clinical evidence that informed national and international treatment guidelines on corticosteroids, anticoagulants, and (hydroxy)chloroquine. Multi-arm platform trials with master protocols and coordinated meta-analyses proved particularly successful, with researchers joining forces to answer the most pressing questions as quickly as possible.

Towards compatibility of EUnetHTA JCA methodology and German HTA: a systematic comparison and recommendations from an industry perspective.

OBJECTIVE: The transferability of the EU joint clinical assessment (JCA) reports for pharmaceuticals for the German benefit assessment was evaluated by systematically comparing EU JCA and German clinical assessments (CA) based on established assessment elements for HTA and assessing the potential impact of differences on Federal Joint Committee (Gemeinsamer Bundesausschuss, G-BA) ability to derive the therapeutic added value. METHODS: Identification of all pharmaceuticals undergoing both, EU JCA and German CA between January 2016-June 2020. Qualitative review and data extraction from the assessments, assessment of methodological differences using a hierarchical model. Recommendations for harmonisation were developed and consented with pharmaceutical industry stakeholders. RESULTS: Differences with potentially major impact: (1) View on differing treatment algorithms and definition of corresponding subpopulations/respective comparators. (2) Clinical relevance of surrogate/intermediate endpoints. Inclusion of different/surrogate morbidity endpoints resulting in different relative effectiveness conclusions. (3) Tolerance of study interventions not used according to marketing authorisation. (4) Different operationalisation and/or weighting of individual safety endpoints leading to differing relative safety conclusions. Differences with potentially minor impact: (1) Disagreement in risk of bias assessment for overall survival and its robustness against study limitations. (2) Use of patient-reported outcome symptom scales as measurements for health-related quality of life instruments. CONCLUSION: While many synergies between EU JCA and German CA exist, we identified several aspects in HTA methodology that would benefit of harmonisation and ensure the transferability of future EU JCA to the German HTA process without duplicated evaluation requirements. For those, a set of recommendations was developed.