Two articles and a commentary in the New England Journal of Medicine further explore the question of geographic variation in health care delivery and what factors may explain that variation. (NEJM Article) The first article looked at variation in diagnostic practices and employed a method of looking at changes when a beneficiary moved. The analysis showed that moving to a high intensity region resulted in more diagnostic testing, more recorded chronic conditions and higher risk scores than for similar patients who didn’t move, with no difference in survival. Of greatest concern, however, is that variable testing and subsequent assignment of diagnoses potentially biases the whole body of research that relies on diagnostic codes for analysis and reimbursement systems which use diagnoses in doing case mix adjustments.
The second article sought to look more carefully at factors accounting for regional variation in practice intensity. Previous research had identified that a relatively small fraction of the variation was due to health status. This study looked more closely at three factors: additional measures of health status; presence of supplemental coverage; and area-level measures of supply. After applying these factors, the difference in spending from the highest to lowest areas was reduced from 52% to 33%, which is still a significant variation. The reduction was largely due to health status and demographic differences. Supply did not seem to affect spending.
We would expect that individual physicians would differ in how they might treat the same patient. What is interesting is that apparently multiple physicians in the same geographic area show the same patterns of variation. The mechanism for this almost certainly has to be some explicit or implicit understanding about the appropriate way to practice or some ethos that accepts, even encourages, taking every possible step to aid a patient and/or overutilization to maximize income. While geographic variation analysis may identify areas that appear to have abusive practice patterns, the remedy almost certainly needs to be conducted on an individual physician basis; it isn’t really fair to assume every doctor is responsible, especially when data is available to identify specific physician practice patterns.