Mortality following bone metastasis and skeletal-related events among patients 65 years and above with lung cancer: A population-based analysis of U.S. Medicare beneficiaries, 1999-2006

BACKGROUND: To quantify the impact of bone metastasis and skeletal-related events (SREs) on mortality among older patients with lung cancer. MATERIALS AND METHODS: Using the linked Surveillance, Epidemiology and End Results-Medicare database, we identified patients aged 65 years or older diagnosed with lung cancer between July 1, 1999 and December 31, 2005 and followed them to determine deaths through December 31, 2006. We classified patients as having possible bone metastasis and SREs using discharge diagnoses from inpatient claims and diagnoses paired with procedure codes from outpatient claims. We used Cox regression to estimate mortality hazards ratios (HR) among patients with bone metastasis with or without SRE, compared to patients without bone metastasis. RESULTS: Among 126,123 patients with lung cancer having a median follow-up of 0.6 years, 24,820 (19.8%) had bone metastasis either at lung cancer diagnosis (9,523, 7.6%) or during follow-up (15,297, 12.1%). SREs occurred in 12,665 (51%) patients with bone metastasis. The HR for death was 2.4 (95% CI = 2.4-2.5) both for patients with bone metastasis but no SRE and for patients with bone metastasis plus SRE, compared to patients without bone metastasis. CONCLUSIONS: Having a bone metastasis, as indicated by Medicare claims, was associated with mortality among patients with lung cancer. We found no difference in mortality between patients with bone metastasis complicated by SRE and patients with bone metastasis but without SRE.