Lymph node metastasis (LNM) is common in patients with papillary thyroid cancer (PTC), and deciding the scope of surgery and postoperative follow-up depend on appropriately estimating the risk of LNM. As a novel composite indication that combines lipid metabolism and inflammation, the platelet-to-high-density lipoprotein ratio (PHR) has not yet been shown to be associated with PTC LNM. This study aims to evaluate the association between PHR and LNM in patients with PTC using a propensity score-matched (PSM) cohort, identify clinically significant data, ultrasound, and pathological features, and construct a nomogram model in conjunction with PHR, while also exploring the association between other composite indicators and LNM.

We gathered information on 784 PTC patients who had surgery at the First Hospital of Lanzhou University's Department of Thyroid Surgery between June 2023 and September 2025. 236 patients in all were eventually included in the trial after being screened in accordance with the inclusion and exclusion criteria. Gather general patient data, complete blood counts, ultrasound results, BRAF V600E mutation test results, preoperative biochemical tests (including lipid profiles), and postoperative pathology reports (including capsular-invasion and LNM status). A total of 162 patients (81 pairs) were eventually included in the trial following a 1:1 propensity score match for age, sex, and body mass index (BMI). PHR, the ratios of triglycerides to high-density lipoprotein (THR), low-density lipoprotein to high-density lipoprotein (LHR), total cholesterol to high-density lipoprotein (TCHR), white blood cells to high-density lipoprotein (WHR), and neutrophils to high-density lipoprotein (NHR) are among the composite indicators that are analyzed. A nomogram was created and characteristics associated with LNM were screened using univariate and multivariate logistic regression. The area under the receiver operating characteristic curve (AUC), calibration curve, and decision curve analysis (DCA) were used to assess the model's degree of calibration and discrimination.

Following PSM, demographic traits such age, sex, and BMI were balanced between the LNM and non-LNM groups ( P > 0.05). Calcification (OR = 2.895, 95% CI 1.395–6.183, P = 0.005), capsularinvasion (OR = 2.276, 95% CI 1.111–4.756, P = 0.026), and PHR (OR = 1.007, 95% CI 1.001–1.014, P = 0.0376) were found to be independently linked to LNM. The multivariate analysis revealed that the remaining five composite indices (THR, LHR, TCHR, WHR, and NHR) were not statistically significant ( P > 0.05). The nomogram model based on PHR, calcification, and capsularinvasion had an AUC of 0.715; the model's calibration and clinical net benefit were deemed satisfactory by the DCA and calibration curves.

In patients with PTC, elevated PHR, calcification, and capsularinvasion are independent risk factors for LNM. Assisting in the evaluation of patients' risk of LNM and offering direction for the creation of postoperative follow-up regimens, the three-variable logistic regression model exhibits moderate discriminatory power and a definite clinical net benefit. The clinical applicability and generalizability of this approach require additional confirmation through prospective, multicenter investigations because this study was retrospective, single-center, and lacked external validation.