Objective:

To identify factors associated with successful levothyroxine (L-T4) withdrawal in patients with primary hypothyroidism and to develop a clinical prediction model.

Approach:

• Study Design: Retrospective cohort study including patients with primary hypothyroidism who attempted L-T4 withdrawal between January 2016 and October 2024.
• Data Collection: Collected baseline data including sociodemographic characteristics, medication-related indices, clinical classification, and laboratory parameters.
• Analysis: Used univariate and multivariable logistic regression to identify independent predictors and construct a nomogram. Assessed model performance using AUC, Hosmer-Lemeshow test, and bootstrap resampling.

Key Findings:

• 35.5% of patients achieved successful L-T4 withdrawal.
• Younger age (OR = 0.901, 95% CI: 0.852–0.953, P < 0.001) and subclinical hypothyroidism (OR = 4.879, 95% CI: 1.343–17.723, P = 0.016) were associated with higher likelihood of successful withdrawal.
• TPOAb positivity (OR = 0.150, 95% CI: 0.040–0.556, P = 0.005) and heterogeneous thyroid echotexture (OR = 0.155, 95% CI: 0.032–0.751, P = 0.021) were associated with lower likelihood of success.
• The predictive model showed excellent discrimination (AUC = 0.899, 95% CI: 0.840–0.957, P < 0.001).

Interpretation:

Younger age, subclinical hypothyroidism, negative TPOAb, and homogeneous thyroid echotexture are associated with a higher likelihood of successful L-T4 withdrawal.

Limitations:

• Single-center study may limit generalizability.
• Retrospective design may introduce selection bias.

Conclusion:

The nomogram model may facilitate pre-withdrawal risk stratification and individualized follow-up planning.