Fig. 1.

Study design. Using EHRead technology (see Methods section for further details), the unstructured clinical data from patients’ EHRs were extracted and analyzed at two different time windows, namely, Baseline and Follow-Up. For all CKD-HD patients, the index date was defined as the timepoint when diagnostic criteria for either HD or SHPT were first met; the baseline period considered the time window between −6 months and +1 month from the index date. Follow-up analyses were performed at 6 and 12 months following the index date, considering a temporal window of ±3 months for data extraction around each timepoint. From a source population of 3,290,365 individuals, a total of 623 patients diagnosed with SHPT undergoing HD were detected. Of these, the final analysis sample comprised 282 patients with available PTH information. NLP, natural language processing; SHPT, secondary hyperparathyroidism; CKD-HD, chronic kidney disease undergoing hemodialysis; PTH, parathyroid hormone.