Lamont Elizabeth B, Dias Lauren E, Lauderdale Diane S
Massachusetts General Hospital Cancer Center, Boston, MA, USA.
J Gen Intern Med. 2007 Aug;22(8):1166-71. doi: 10.1007/s11606-007-0256-7. Epub 2007 Jun 19.
Randomized trials show non-steroidal anti-inflammatory drugs (NSAIDs) reduce precancerous polyps. Observational studies of the NSAID aspirin (ASA) suggest that it reduces invasive colorectal cancer (CRC) incidence, but because ASA use may also be a marker for healthy behaviors, these studies may be subject to selection bias. We sought to estimate the effectiveness of NSAIDs in CRC prevention in the population of elderly Medicare beneficiaries, minimizing this selection bias.
With National Ambulatory Medical Care Survey data, we find that patients with a diagnosis of osteoarthritis (OA) are 4.4 times more likely to concurrently have NSAID use documented than patients without such a diagnosis. We use this figure to estimate the expected NSAID-mediated reduction in CRC risk associated with a diagnosis of OA. Using Survival Epidemiology and End-Results (SEER)-Medicare data, we compare cases of elderly Medicare beneficiaries diagnosed with CRC in 1995 to persons without CRC to determine if their odds of antecedent OA differ.
We estimate the expected NSAID-mediated reduction in CRC associated with an OA diagnosis to be between 6 and 16% (i.e., RR, 0.84-0.94). In the SEER-Medicare data, we find that individuals with a diagnosis of OA in Medicare claims in the previous 3 years had 15% lower odds of being diagnosed with CRC than individuals whose claims did not reflect antecedent OA (OR 0.85, 95%CI 0.80-0.91).
This case-control study finds that elderly Medicare beneficiaries with histories of OA have 15% lower odds of developing CRC. These results are consistent with a preventive role for NSAIDs in CRC among the elderly.
随机试验表明，非甾体抗炎药（NSAIDs）可减少癌前息肉。对NSAIDs阿司匹林（ASA）的观察性研究表明，它可降低浸润性结直肠癌（CRC）的发病率，但由于使用ASA也可能是健康行为的一个标志，这些研究可能存在选择偏倚。我们试图在老年医疗保险受益人群中估计NSAIDs在预防CRC方面的有效性，以尽量减少这种选择偏倚。
利用国家门诊医疗调查数据，我们发现诊断为骨关节炎（OA）的患者同时有NSAIDs使用记录的可能性是未诊断出该病患者的4.4倍。我们用这个数字来估计与OA诊断相关的NSAIDs介导的CRC风险预期降低值。利用生存流行病学与最终结果（SEER）-医疗保险数据，我们将1995年诊断为CRC的老年医疗保险受益人与未患CRC的人进行比较，以确定他们先前患OA的几率是否不同。
我们估计与OA诊断相关的NSAIDs介导的CRC预期降低值在6%至16%之间（即相对风险，0.84 - 0.94）。在SEER-医疗保险数据中，我们发现过去3年医疗保险理赔中有OA诊断的个体被诊断为CRC的几率比理赔中未显示先前有OA的个体低15%（比值比0.85，95%置信区间0.80 - 0.91）。
这项病例对照研究发现，有OA病史的老年医疗保险受益人患CRC的几率低15%。这些结果与NSAIDs在老年人CRC预防中的作用一致。
