MATERIALS AND METHODS
We conducted a retrospective study, including all patients with CF who were registered and followed between April 2000 and April 2020 in the CF Center at University Hospital (Dr. José E. González in Monterrey Mexico). Demographic, clinical, and biological variables were documented, such as gender sex, age at diagnosis, SES, pancreatic status, CFTR genotypes, and diagnosis of chronic infection with P. aeruginosa at 6 years. Age at diagnosis was categorized as ≤ 2 years, 3 – 18 years, > 18 years. SES was evaluated using the Asociación Mexicana de Agencias de Inteligencia de Mercado y Opinion (AMAI) score, with patients divided in high (AB, C+, and C) and low socioeconomic levels (C,D, and E)16. A pancreatic-insufficient or pancreatic-sufficient classification was based on enzyme usage.2 Genotype was classified as homozygous for F508Δ mutation, heterozygous for F508Δ mutation, and other or missing. Quarterly sputum or oropharyngeal swab bacteriology in the first 6 years were evaluated to detect chronic infection withP. aeruginosa, using Leeds Criteria.17
The Mexican health system is complex; it is comprised of two sectors: public and private. The public sector includes: (1) Social security institutions [Instituto Mexicano del Seguro Social (IMSS), Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE), Petróleos Mexicanos (PEMEX), Ministry of Defense (SEDENA), Ministry of the Navy (SEMAR), and (2) programs that cover the population without social security [Ministry of Health (SSa), State Health Services (SESA), IMSS-Oportunidades (IMSS-O), Seguro Popular (SPS)]. The private sector is comprised of insurance companies and service providers, working in both private clinics and hospitals.18 Access to tobramycin varies according to health coverage; currently, patients belonging to ISSSTE, PEMEX, SEDENA SEMAR, SPS, and the majority of patients from private health insurance companies have access to this drug.
This study was approved by the Institutional Research Ethics Committee.