Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
Int J Cardiol. 2011 Apr 14;148(2):209-13. doi: 10.1016/j.ijcard.2009.09.566. Epub 2009 Dec 3.
Meta-analyses are increasingly used to summarise observational data however a literature meta-analysis (LMA) may give different results to the corresponding individual patient meta-analysis (IPMA). This study compares the published results of equivalent LMAs and IPMAs, highlighting factors that can affect the results and therefore impact on clinical interpretation of meta-analyses.
Univariate results from published meta-analyses of prospective observational outcome data were compared, as were the number of studies, patients and length of follow-up. The absolute difference in survival was calculated. The association between severe diastolic dysfunction (RFP) and death post acute myocardial infarction (AMI) and in chronic heart failure (HF) were used as clinical examples.
The IPMA hazard ratio was lower that the LMA odds ratio: AMI hazard ratio 2.67 (95% confidence interval 2.23 to 3.20), odds ratio 4.10 (3.38 to 4.99); HF hazard ratio 2.42 (2.06 to 2.83), odds ratio 4.36 (3.60 to 5.04). The IPMAs contained most of the studies from the LMAs as well as additional unpublished data, and a longer length of follow-up was available in the IPMAs (AMI 3.7 vs 2.6 yr, HF 4.0 vs 1.5 yr). Restricting analysis to the same studies in both the LMA and IPMA resulted in a similar difference in effect sizes between methods to those found in the published analyses.
The result of a meta-analysis is affected by whether study level or individual patient data have been used, and the variant of analysis that is required. Awareness and consideration of these factors is important for clinical interpretation of meta-analyses.
荟萃分析越来越多地用于总结观察性数据，但文献荟萃分析（LMA）的结果可能与相应的个体患者荟萃分析（IPMA）不同。本研究比较了等效 LMA 和 IPA 的已发表结果，强调了可能影响结果的因素，从而影响荟萃分析的临床解释。
比较了前瞻性观察性结局数据荟萃分析的已发表荟萃分析的单变量结果，以及研究数量、患者数量和随访时间。计算了生存的绝对差异。使用急性心肌梗死（AMI）后严重舒张功能障碍（RFP）和慢性心力衰竭（HF）的死亡以及慢性心力衰竭的死亡作为临床实例。
IPMA 风险比低于 LMA 优势比：AMI 风险比 2.67（95%置信区间 2.23 至 3.20），优势比 4.10（3.38 至 4.99）；HF 风险比 2.42（2.06 至 2.83），优势比 4.36（3.60 至 5.04）。IPMA 包含了大多数来自 LMA 的研究以及额外的未发表数据，并且 IPM 中提供了更长的随访时间（AMI 为 3.7 年，HF 为 4.0 年）。在 LMA 和 IPMA 中都将分析限制在相同的研究中，结果发现两种方法之间的效果大小差异相似。
荟萃分析的结果受到使用研究水平或个体患者数据以及所需的分析变体的影响。对这些因素的认识和考虑对于荟萃分析的临床解释非常重要。
