Mitchell Jean M, Gresenz Carole Roan
Georgetown University, Washington, DC, USA.
Med Care Res Rev. 2022 Feb;79(1):141-150. doi: 10.1177/1077558720980552. Epub 2020 Dec 17.
Relatively little is known about the extent and effects of horizontal mergers among physician specialists. We developed and implemented a methodology to document changes in physician practice structure resulting from horizontal integration among urology groups. We merged cancer registry records from four large states with Medicare Part B claims to identify all urologists who treated men with prostate cancer. We added information from SK & A surveys and extensive internet searches to assign a practice structure to each urologist-year (2005-2014). Horizontal integration among small urology groups led to a sharp increase in the proportion of urologists who belong to large urology practices with ownership in intensity modulated radiation therapy and/or anatomical pathology services. By 2014, more than half of New Jersey urologists and about 43% of urologists in Florida and Texas were members of such large practices, whereas small percentages (7%-16%) were employed by a health system. In contrast, more than 27% of California urologists were employed but only 17.5% had ownership in intensity modulated radiation therapy and/or pathology services. Importantly, we found our indicators of market share of urologists associated with each practice structure type were highly concordant with indicators of market share based on number of prostate cancer episodes treated by each practice structure type.
对于内科专科医生之间横向合并的程度及影响，我们了解得相对较少。我们开发并实施了一种方法，以记录泌尿外科小组之间横向整合所导致的医生执业结构变化。我们将四个大州的癌症登记记录与医疗保险B部分索赔记录合并，以识别所有治疗前列腺癌男性患者的泌尿科医生。我们补充了SK&A调查和广泛的互联网搜索信息，为每位泌尿科医生的年度（2005 - 2014年）确定执业结构。小型泌尿外科小组之间的横向整合导致属于拥有调强放射治疗和/或解剖病理学服务所有权的大型泌尿外科机构的泌尿科医生比例急剧增加。到2014年，新泽西州超过一半的泌尿科医生以及佛罗里达州和得克萨斯州约43%的泌尿科医生是此类大型机构的成员，而受雇于医疗系统的比例较小（7% - 16%）。相比之下，加利福尼亚州超过27%的泌尿科医生受雇，但只有17.5%拥有调强放射治疗和/或病理学服务的所有权。重要的是，我们发现与每种执业结构类型相关的泌尿科医生市场份额指标与基于每种执业结构类型治疗的前列腺癌病例数的市场份额指标高度一致。
