分层整群随机试验中过分散零膨胀计数数据分析方法的实证比较

An empirical comparison of methods for analyzing over-dispersed zero-inflated count data from stratified cluster randomized trials.

作者信息

Borhan Sayem, Kennedy Courtney, Ioannidis George, Papaioannou Alexandra, Adachi Jonathan, Thabane Lehana

机构信息

Department of Health Research Methods, Evidence and Impact, McMaster University, Hamilton, ON, Canada.

Biostatistics Unit, Research Institute of St Joseph's Healthcare, Hamilton, ON, Canada.

出版信息

Contemp Clin Trials Commun. 2020 Feb 1;17:100539. doi: 10.1016/j.conctc.2020.100539. eCollection 2020 Mar.

DOI:10.1016/j.conctc.2020.100539

PMID:32072073

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC7015989/

Abstract

BACKGROUND

The assessment of methods for analyzing over-dispersed zero inflated count outcome has received very little or no attention in stratified cluster randomized trials. In this study, we performed sensitivity analyses to empirically compare eight methods for analyzing zero inflated over-dispersed count outcome from the Vitamin D and Osteoporosis Study (ViD) - originally designed to assess the feasibility of a knowledge translation intervention in long-term care home setting.

METHOD

Forty long-term care (LTC) homes were stratified and then randomized into knowledge translation (KT) intervention (19 homes) and control (21 homes) groups. The homes/clusters were stratified by home size (<250/> = 250) and profit status (profit/non-profit). The outcome of this study was number of falls measured at 6-month post-intervention. The following methods were used to assess the effect of KT intervention on number of falls: i) standard Poisson and negative binomial regression; ii) mixed-effects method with Poisson and negative binomial distribution; iii) generalized estimating equation (GEE) with Poisson and negative binomial; iv) zero inflated Poisson and negative binomial - with the latter used as a primary approach. All these methods were compared with or without adjusting for stratification.

RESULTS

A total of 5,478 older people from 40 LTC homes were included in this study. The mean (=1) of the number of falls was smaller than the variance (=6). Also 72% and 46% of the number of falls were zero in the control and intervention groups, respectively. The direction of the estimated incidence rate ratios (IRRs) was similar for all methods. The zero inflated negative binomial yielded the lowest IRRs and narrowest 95% confidence intervals when adjusted for stratification compared to GEE and mixed-effect methods. Further, the widths of the 95% confidence intervals were narrower when the methods adjusted for stratification compared to the same method not adjusted for stratification.

CONCLUSION

The overall conclusion from the GEE, mixed-effect and zero inflated methods were similar. However, these methods differ in terms of effect estimate and widths of the confidence interval.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01398527. Registered: 19 July 2011.

摘要

背景

在分层整群随机试验中，对过分散零膨胀计数结果分析方法的评估很少受到关注或根本未被关注。在本研究中，我们进行了敏感性分析，以实证比较八种分析维生素D与骨质疏松症研究（ViD）中零膨胀过分散计数结果的方法——该研究最初旨在评估长期护理机构环境中知识转化干预措施的可行性。

方法

将40所长期护理（LTC）机构进行分层，然后随机分为知识转化（KT）干预组（19所机构）和对照组（21所机构）。这些机构/群组按机构规模（<250/> = 250）和盈利状况（盈利/非营利）进行分层。本研究的结局是干预后6个月测量的跌倒次数。采用以下方法评估KT干预对跌倒次数的影响：i）标准泊松回归和负二项回归；ii）泊松分布和负二项分布的混合效应法；iii）泊松和负二项分布的广义估计方程（GEE）；iv）零膨胀泊松回归和负二项回归——后者作为主要方法。所有这些方法均比较了是否调整分层。

结果

本研究纳入了来自40所LTC机构的共5478名老年人。跌倒次数的均值（=1）小于方差（=6）。此外，对照组和干预组中跌倒次数分别有72%和46%为零。所有方法估计的发病率比（IRR）方向相似。与GEE和混合效应法相比，调整分层后，零膨胀负二项回归得出的IRR最低，95%置信区间最窄。此外，与未调整分层的相同方法相比，调整分层的方法得出的95%置信区间宽度更窄。