Abstract
Aims: The study aimed at assessing the prevalence and clinical features of vitamin B12 deficiency in hypothyroid patients and to evaluate clinical response to vitamin B12 replacement therapy.
Methods: A total of 204 vitamin B12 deficient patients with primary hypothyroidism who attended the thyroid clinic at the nuclear medicine department of Atomic Energy Medical Centre Karachi, were included in the study. Signs and symptoms, haemoglobin (Hb), mean corpuscular volume (MCV), thyroid function tests and B12 levels were recorded. Patients with low levels of B12 or who had symptoms suggestive of B12 deficiency were given oral vitamin B12 treatment and monitored for improvement.
Results: A total of 204 hypothyroid patients (197 females, 7 males) were evaluated. 92 of 204 patients (45.09%) had low vitamin B12 levels. Depression (p value 0.000082), weakness (p value 0.0018), numbness (p value 0.022), paraesthesia (p value 0.018), and impaired memory (p value 0.027) were statistically significant in B12-deficient hypothyroid patients. B12-deficient patients had increased prevalence of anaemia than the sufficient group (32.6% vs. 22.02%). 92 B12-deficient and 70 B12-sufficient patients with symptoms of B12 deficiency were started on oral vitamin B12 and improvement noted.
Conclusion: There is a high (45%) prevalence of B12 deficiency in hypothyroid patients. Screening of vitamin B12 levels should be undertaken in all hypothyroid patients in the early course of the disease as it is a potentially reversible condition. Weakness, numbness and neuropsychiatric symptoms point towards B12 deficiency. Replacement of B12 leads to improvement in symptoms; however, placebo effect should be taken into consideration.