Evaluation of adherence to oral medications in permanent hypoPT patients is extremely important for preventing hypocalcemia related symptoms without causing side effects such as nephrocalcinosis. There is no previous study in the literature evaluating the drug compliance and related factors in patients with hypoPT. The quality of life evaluated with “Short Form 36 and Hospital Anxiety and Depression scale” was reported to be lower in hypoPT patients due to lifelong treatment burden of medications, need for hospitalizations or frequent visits and fluctuating serum Ca levels . Post-surgical hypoPT was also found to be correlated with lower quality of life scores compared with other hypoPT subtypes in that study. Despite calcium and active vitamin D replacement, some patients may still experience physical and emotional symptoms regardless of the serum Ca level since parathyroid hormone receptors are distributed in central nervous system and muscle tissues .
In this study, the emergency admittance because of hypoPT or its complications was found 26.6% of the patients. In a previous study 42 of 120 patients (33%) had at least one hypoPT related emergency admittance after diagnosis . The lower rate of disease related emergencies in our patient group may be related to younger age compared with the mentioned study. Most common hypo PT symptom was muscle weakness in the previous studies. Sikjaer et al reported that muscle functions are affected more severely in patients with concomitant hypothyroidism and hypo PT compared to hypo PT alone and control groups .
In this study prevalence of psychiatric diseases (depression and anxiety disorders) in hypo PT patients was 20.3%. Like our study, previous reports suggested more prevalent anxiety, phobia and depression compared to control group despite keeping the calcium levels in the normal range [18, 19]. In a cohort of patients in Denmark, hospitalization due to depression, bipolar disorder and infections were higher in hypoPT patients compared to controls . In our study almost 60% of patients had worries about calcium carbonate side effects and 13.3% had worries about calcitriol adverse effects. The most common source of anxiety was giving harm to kidneys or gastrointestinal disturbances such as bloating and constipation. Twenty percent of our study group had history of nephrolithiasis.
To our knowledge there is scarce indeed no study in the literature evaluating drug compliance in post-surgical hypo PT patients. Compliance to calcium and vitamin D replacement was previously studied in patients with osteoporosis [21, 22]. But those patient populations are different from ours regarding the advanced age and significant female predominance. In a previous study, using Morisky-Green test, osteoporosis patients detected to have poor compliance to calcium and vitamin D. The major determinants of drug incompliance were reported to be memory problems and high costs . In our patient group all patients had social health security covering the costs so the major reason of incompliance was thought to be side effects. In a study by Branco et al only two of every ten patients who received a prescription for Ca and vitamin D persisted and complied properly with the treatment 1 year after beginning it . The possible explanations for incompliance included the presence of psychiatric disorders, cognitive impairment, provider-patient relationship, complexity of treatment, and barriers to care. Physician’s attitude was reported to be an important factor to increase the awareness of the patients about the benefits of the treatment and risks of giving drug holidays. In a previous study it was shown that specific activities aimed to strengthen motivation of the patients as scheduling periodic follow-up visits every 6 months seem ed to increase the adherence to calcium and vitamin D supplementations after only 6 months . In that study drug adherence was correlated with age as the youngers had more compliance in contrast to our study result
In our study the motivation and knowledge about the drugs and adherence level was higher compared to previous ones conducted in different patient populations. That might be due to the highly selected group of individuals in this study who admitted to a tertiary endocrine center with postoperative hypoparathyroidism. The major determinant of incompliance was disease duration which can be explained by patient exhaustion. We cant draw direct conclusions from the previous reports since they were conducted in osteoporotic patients in whom drug adherence is not as vital as in hypo PT. Motivation score is lower for calcium than calcitriol in this study possibly because of the larger and tablet sizes and the bitter taste.
Our study is the first one evaluating drug compliance and factors effecting it in post-surgical hypo PT. The limitation is the small number of patients and lack of laboratory data reflecting the disease control status.
In conclusion, one third of patients in our study lack motivation to use calcium whereas half of the patients’ experiences anxiety about drug related side effects. Drug motivation further decrease as the disease duration increase. This is a preliminary study showing that vital calcium and active vitamin D intake may be interrupted due to side effect anxiety and motivation can be increased by frequent visits and acknowledging the patient about the deleterious effects of drug withdrawal.