Came across the following link. What is surprising that these people were treated due to their low basal temp alone:-
Physician Broda Otto Barnes‘ dissertation, published in 1932, was related to the function of the thyroglobulin protein. In the beginning of his medical practice, he noticed that many of his patients had symptoms that were similar to mild hypothyroidism. After noticing this, he began prescribing desiccated thyroid to a large part of his patients.
Barnes didn’t diagnose hypothyroidism based on his patients’ blood tests or basal metabolism (BMR), but instead he claimed that basal temperature is a more accurate marker of thyroid hormone function and health. His essay on that subject, Basal temperature versus basal metabolism, was published in 1942 in The Journal of the American Medical Association. In that article, Barnes wrote that he told his patients to measure their axillary temperature immediately after waking up. Temperature lower than 36.5 celcius (97.8F) was an important indicator of hypothyroidism and thus, a need for a prescription of desiccated thyroid.
I think it’s wise to mention one of Barnes’ other papers too, Prophylaxis of ischaemic heart-disease by thyroid therapy (1959), published in Lancet. The paper shows that thyroid treatment lowers high cholesterol levels very reliably.
For his study, Barnes chose 80 persons who had high cholesterol (>200mg/dl). Usually the cholesterol levels fell to the range of 170-200mg/dl or 4.4-5.2 mmol/l after the patients had been on their thyroid medication for a sufficient duration