Figure 1. Diagram of Study Population, Including Index Mastectomy and Immediate and Subsequent Reconstruction After Mastectomy.

^aWe required all women included in the study population to have at least 90 days of insurance coverage after mastectomy. The women with subsequent breast reconstruction procedure(s) were more likely to have at least 1 year of health insurance coverage after mastectomy than those without a subsequent reconstruction procedure (5763 [89.7%] vs 8194 [75.4%]; P < .001). Among women with less than 1 year of coverage after mastectomy, those with a subsequent procedure had a greater median number of days of health insurance coverage (295 vs 227 days; P < .001).

^bImmediate reconstruction (IR) occurred within 7 days of mastectomy.

^cIncludes tissue expander or permanent implant.

^dIncludes use of an autologous tissue flap (abdominal, buttock, and back tissue transferred on its vascular pedicle or by free tissue transfer microsurgical anastomosis techniques).

^eIncludes use of an implant and autologous tissue flap, as defined above.

^fIncludes a woman’s first subsequent reconstruction 8 to 365 days after the index mastectomy. The first subsequent implant reconstruction (secondary reconstruction [SR] or delayed reconstruction [DR]) was performed a median of 156 days after mastectomy (interquartile range [IQR], 112-210 days); the first subsequent autologous reconstruction (with or without implant), a median of 232 days (IQR, 157-294 days) after mastectomy (P < .001). Implant DR was performed at a later date after mastectomy than was implant SR (181 days [IQR, 113-252 days] vs 155 days [IQR, 112-207 days]; P < .001), and autologous DR was performed at a later date than was autologous SR (250 days [IQR, 189-299 days] vs 209 days [IQR, 133-279 days]; P = .007).

^gPerformed in patients without IR.

^hIndicates no implant or flap reconstruction within 365 days of mastectomy. Implant procedures consistent with contralateral procedures were included in this group (eg, implant insertion in a woman with unilateral mastectomy without immediate reconstruction but with other code[s] consistent with secondary implant procedures [eg, capsulectomy]). Because we only required 90 days of health insurance enrollment after mastectomy, some women may have had DR at 91 to 365 days that we could not identify owing to cessation of insurance coverage.