Patient-level drivers of increased levothyroxine (LT4) prescribing: an analysis of greater manchester population health records (2010-2024)

Michael Stedman; Suhani Bahl; Peter Taylor; Lakdasa Premawardhana; Buchi Okosieme; Colin Dayan; Salman Razvi; Simon Pearce; Adrian Heald

doi:10.1530/endoabs.117.P248

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Endocrine Abstracts (2026) 117 P248 | DOI: 10.1530/endoabs.117.P248

SFEBES2026 Poster Presentations Thyroid (34 abstracts)

Patient-level drivers of increased levothyroxine (LT4) prescribing: an analysis of greater manchester population health records (2010–2024)

Michael Stedman ¹ , Suhani Bahl ² , Peter Taylor ² , Lakdasa Premawardhana ³ , Buchi Okosieme ³ , Colin Dayan ³ , Salman Razvi ⁴ , Simon Pearce ⁵ & Adrian Heald ⁶

Author affiliations

¹Res Consortium, Andover, United Kingdom; ²Cardiff University, Cardiff, United Kingdom; ³University of Cardiff, Cardiff, United Kingdom; ⁴University of Newcastle, Newastle, United Kingdom; ⁵University of Newcastle, Newcastle, United Kingdom; ⁶Salford Royal Hospital, Salford, United Kingdom

Introduction: Levothyroxine (LT4) prescriptions in England have increased from 9 million annually in 2000 to 30 million in 2024, outpacing the incidence of overt hypothyroidism. This study used patient-level primary-care-data to quantify increase in LT4-treated patients identify demographic/clinical characteristics associated with this growth.

Methods: Data was available from patients who received LT4 prescriptions in Greater Manchester (population = 2.85million) 2010-2024. Patients were included with diagnosis of hypothyroidism /no recorded diagnosis (other thyroid disorders were excluded). The overall number of new patients recorded over the 14-years was compared as percentage to the 2010-patient baseline to give Average Annual Rate of Increase (AARI) across strata of sex/age at treatment start/average daily dose/BMI. Demographic changes were accounted for using prescribing rates calculated from the 2011England population applied to the 2023population.

Results: Of 990,000 patients with recorded thyroid function tests, 106,000 received LT4. Of the cohort included in the analysis, 41,689 were already on medication and 58,070 patients started treatment post-2010. This gave an overall 9.8% AARI. Significant, disproportionate growth was observed in specific subgroups: Dose: 4% Patients taking very low doses (0–39 mg/day) showed a 47% AARI. The 17% on 40-79 mg/day showed a 20% AARI. Age: The 20-39 age group, 11% of the 2010 cohort, showed a 22% AARI. The 80+ age group with 3% in 2010, showed 16% AARI. Sex: Males, with 17% of the 2010 cohort, showed a 13% AARI. Demographic changes accounted for 4,033 of the increase, together with subgroup growth (low daily doses/age 20–39/80+/males), these collectively accounting for estimated 62% of overall patient increase (with allowance for double-counting). BMI/rate of treatment cessation remained constant.

Conclusion: LT4 use has more than doubled, primarily driven by an expansion of treatment into specific patient groups. These shifts strongly suggest a broadening of treatment criteria, explaining a significant portion of the recent years’ growth.