Study of Optimal Replacement of Thyroxine in the ElDerly (SORTED): protocol for a mixed methods feasibility study to assess the clinical utility of lower dose thyroxine in elderly hypothyroid patients: study protocol for a randomized controlled trial

Table 1 SORTED A study assessments

	Pre-screening	Screening	Baseline	Follow-up
Visit			1	2	3	4 (phone call only)
Assessments^a	Within 3 months of baseline visit	Week −4 to −1	Day 0	Week 12 (+/− 7 days)	Week 24 (+/− 7 days)	Week 25 (+/− 3 days)
Identification and initial approach (including provision of PIS)	X
Eligibility criteria checked (as per routine clinical practice)	X
Written informed consent (including discussion of study in detail, questions answered)		X
Physical examination (height,^e weight, blood pressure, pulse)			X		X
Venepuncture			X ^b	X ^c	X^d
Clinical history (relevant medical history, medication list/history)			X
Participant-completed questionnaires (ThyDQoL, ThySRQ, EQ-5D)			X		X
Nurse-administered questionnaires (FRAT, TUG)			X		X
Randomization (after all eligibility criteria checked and written informed consent obtained)			X
Study medication prescribed and dispensed (following LT4 dose assessment at visit 2 only)			X	X
Study medication compliance checks				X	X
Concomitant medication			X	X	X
Adverse events				X	X
Serious adverse events				X	X	X

^a Study-specific procedures must only be performed once written informed consent is obtained from the participant; ^b 10 ml blood: TSH, FT4, FT3, thyroid peroxidase antibodies, total cholesterol, HDL, triglycerides, serum CTX; ^c 5 ml blood: TSH, FT4, FT3 only; ^d 10 ml blood: TSH, FT4, FT3, total cholesterol, HDL, triglycerides, serum CTX; ^e height to be measured at the baseline visit only.
FT3: free triiodothyronine (thyroid hormone); FT4: free thyroxine; HDL: high-density lipoprotein; serum CTX: serum collagen type-1 cross-linked C-telopeptide; TSH: thyroid stimulating hormone, PIS: participant information sheet.