Comorbidities, Concomitant Medications, and Diet as Factors Affecting Levothyroxine Therapy: Results of the CONTROL Surveillance Project

Abstract

BackgroundThe CONTROL Surveillance Project was a comprehensive patient-based survey conducted among hypothyroid patients undergoing treatment. The primary objective of the study was to specifically quantify the prevalence of factors adversely affecting levothyroxine therapy.MethodsParticipants were selected from a large proprietary database. Those eligible for the study completed a 21-question survey.ResultsOf the eligible hypothyroid patients, 925 (92.5 %) were being treated with levothyroxine monotherapy. The mean age was 60.4 years; 755 (81.6 %) were female and 168 (18.2 %) were male. Almost half of those receiving levothyroxine (435, 47.0 %) had at least one comorbid condition that could adversely affect its absorption: gastroesophageal reflux disease (33.8 % of patients), irritable bowel syndrome (9.7 %), lactose intolerance (7.8 %), or a history of gastric bypass surgery or bowel resection (3.0 %). Other factors reported by many patients that could adversely affect levothyroxine absorption included use of prescription medications (20.6 %) and over-the-counter medications (34.3 %) used to treat comorbid gastrointestinal (GI) conditions; use of dietary supplements (51.8 %, primarily calcium and iron); and intake of foods/beverages high in fiber, iodine, or soy (68.0 %). Of the 13.4 % who reported difficulty controlling their hypothyroid symptoms, significantly more patients with comorbid GI conditions reported such difficulty (7.8 versus 5.6 %, P < 0.01). Frequent changes in levothyroxine dosing (two or more dose changes in the past year) were reported by 8.0 % of survey participants. Those with GI comorbidities were nearly twice as likely to have such changes (5.0 versus 3.0 %, P < 0.01).ConclusionBetter initial workup of patients, including identification of relevant GI comorbidities and allergies, may help in the early detection of factors that may affect the performance of levothyroxine.

The thyroid registry: Clinical and hormonal characteristics of adult indian patients with hypothyroidism

“…It is recommended that all patients with SCH having thyrotropin levels above >10 mIU/L and those with overt hypothyroidism be treated with levothyroxine. [427] A recent report[28] provided some preliminary evidence of benefit in favor of normalizing the serum TSH in patients aged 40–70 years. In this report, thyroxine replacement had shown to reduce the risk of cardiac events in patients with SCH.…”

The Economic Impact of Changing Levothyroxine Formulations in Difficult-to-Treat Hypothyroid Patients: An Evidence-Based Model

“…In the CONTROL Surveillance Study [16], a survey of 925 levothyroxinetreated patients, more than 23.4% of respondents claimed to have experienced one levothyroxine dose or formulation change in the prior 12 months. An additional 8% reported having experienced two or more such changes during the same period of time.…”

“…McMillan et al [16] reported that up to 31% of hypothyroid patients receiving levothyroxine therapy for >2 years require one or more levothyroxine dosage adjustments annually. Common factors that can lead to, or necessitate, levothyroxine dose adjustments include a lack of medication persistence, dosage errors, changes in medical conditions, use of concomitant medications, body mass changes, and dietary habits [10][11][12][13][14][15][16].…”

The Economic Impact of Levothyroxine Dose Adjustments: the CONTROL HE Study

“…Among patients reporting dose changes, the majority (60%) stated that they had experienced one such change; 40% reported two or more such changes. It is important to note than 94% of patients in CONTROL Surveillance reported being treated with levothyroxine for more than 10 years [43]. …”