Hyperprolactinemia in Patients with Subclinical Hypothyroidism in Baghdad, Iraq, 2023

Abstract

Background: Hyperprolactinemia is the most prevalent endocrine disorder in the hypothalamic-pituitary axis. The common causes of hyperprolactinemia can be medications, hypothyroidism, and pituitary disorders. Hypothyroidism and hyperprolactinemia are found to be closely interrelated. Prevalence of hyperprolactinemia in subclinical hypothyroidism (SCH) has been reported in a wide range of 0%– 40% of hypothyroid patients. This study aimed to determine the prevalence and predictors of hyperprolactinemia in subclinical hypothyroidism in Al-Kindy Teaching Hospital in Bagdad, Iraq.  Methods: A cross-sectional study was conducted in the Department of Internal Medicine and in the diabetes and endocrinology center at Al-Kindy Teaching Hospital for nine months. A total of 95 patients who were diagnosed with SCH were recruited in this study. SCH was diagnosed when there are no specific symptoms or signs of thyroid dysfunction, but the patient has an elevated serum TSH in the face of normal circulating thyroid hormone levels. A study questionnaire was designed, and it included baseline characteristics and signs and symptoms of hypothyroidism. Seven ml of fasting blood samples was taken from all the studied patients and sent to the laboratory to measure the required biochemical parameters. Student t-test was used for comparison, and quantitative data were stated as the mean and standard deviation. Pearson correlation was calculated for the correlation between two quantitative variables. P value less than 0.05 was considered statistically significant.

Results: The prevalence of hyperprolactinemia was 21.1%. The proportion of hyperprolactinemia was significantly higher among female patients compared to that in male patients. The mean level of TSH was significantly higher in patients with high prolactin levels when compared to those with normal prolactin levels. On the other hand, the mean levels of pulse rate, T3, and LH were significantly lower in patients with high prolactin levels than that in patients with normal prolactin levels.

Conclusions: Hyperprolactinemia is a considerable problem in patients who complained from SCH, especially in females. The most common signs and symptoms associated with hyperprolactinemia are dry skin, weight gain, constipation, psychosis madness, menorrhagia, and galactorrhea. Evaluation of serum prolactin levels in patients with SCH, especially those with the associated signs and symptoms, is recommended.