Analysis of first-dose fludrocortisone accessibility in patients with salt-wasting congenital adrenal hyperplasia in mainland china: a single-center retrospective study

Abstract Background Salt-Wasting Congenital Adrenal Hyperplasia (SW-CAH) is a life-threatening neonatal endocrine emergency that requires lifelong mineralocorticoid replacement with Fludrocortisone (FC). However, poor FC accessibility remains a major barrier to timely care in low- and middle-income countries (LMICs), even with universal newborn screening (NBS) programs. Taking advantage of three sequential phases of local FC supply evolution in southern China, this study evaluated the impact of stepwise improved FC accessibility on early clinical outcomes, treatment escalation risk, and patient-clinician experiences in mainland China. Methods This single-center, retrospective, interrupted time-series natural experiment enrolled 22 infants diagnosed with SW-CAH at the Dongguan Newborn Screening Center between June 1, 2018 and October 31, 2025. Patients were assigned to three phases according to the dominant FC supply model at diagnosis: overseas online purchasing (Phase A, 2018 — 2021), physician-coordinated peer medication assistance (Phase B, 2022 — May 2024), and hospital routine stock (Phase C, June 2024 — 2025). The primary outcome was the rate of high-level treatment, defined as intravenous hydrocortisone plus intravenous potassium-lowering therapy (L2) or hemodialysis added L2 therapy (L3). All analyses focused on the initial treatment episode and short-term neonatal outcomes; long-term maintenance data were excluded. Results The median interval from FC prescription to administration decreased from 121 h (Phase A) to 1 h (Phase C) ( P < 0.001), corresponding to a 99.2% reduction. The high-level treatment rate declined in a stepwise from 57.1% (Phase A) to 37.5% (Phase B) and 16.7% (Phase C) (Cochran-Armitage trend test, P = 0.007). All three cases requiring hemodialysis occurred in Phase A and B, with zero L3 events on Phase C. ROC analysis identified an exploratory cutoff of 150 h for prescription-to-administration interval to predict treatment escalation (AUC = 0.837; sensitivity 100%, specificity 85.7%). Questionnaire surveys showed that improved drug accessibility completely eliminated parental anxiety related to drug shortage and restored professional fulfillment among healthcare staff. Conclusions Institutional hospital formulary stock transformed early SW-CAH care from reactive crisis rescue to proactive electrolyte disorder prevention. The physician-coordinated peer assistance model also provides an effective transitional solution before formal drug marketing approval. This preliminary model (“Dongguan Model”, a single-center exploratory institutional model) offers a replicable, low-cost reference for improving orphan drug accessibility in resource-limited settings, while external validation in larger multicenter cohorts is warranted.