Baseline prolactin monitoring in patients admitted to a specialized psychogeriatric unit.

Sir,

Prolactin levels of more than 28.3 ng/ml for females and 16.5 ng/ml for males are considered as hyperprolactinemia.[1] The long-term effects include increased risks of osteoporosis, breast cancer, prostate cancer, cardiovascular disease,[1] and hypoinsulinemia.[2] These are particularly relevant for older people who are often on multiple medications including antipsychotics. However, hyperprolactinemia is a largely neglected area in this population.

We studied the monitoring and management of hyperprolactinemia, over a year, in patients admitted to a 16-bedded state-funded psychogeriatric unit at Ipswich in the Australian State of Queensland. The study protocol was approved by the quality improvement team at the Clinical Governance Unit in West Moreton Hospital and Health Service. Data were gathered from the following electronic health records: the Consumer Integrated Mental Health Applications (CIMHA), Viewer, and integrated electronic Medical Record (ieMR). Data were analyzed using Statistical Package for the Social Sciences (SPSS) version 22.

Sixty-nine patients were discharged from the unit in that year, consisting of an almost equal number of males (34 [49.3%]) and females (35 [50.7%]), with a mean age of 73.9 years. Many patients (76.8%, n = 53) had only one admission in that year, although 16 had two or more admissions. Commonest diagnoses were recurrent depressive disorder (34.8%), followed by non-affective psychosis (schizophrenia and schizoaffective disorder- 26.1%) and bipolar affective disorder (14.5%). The mean admission duration was 28 days.

Fifty-eight (84.1%) patients were on an antipsychotic, and majority (56.9%, n = 33) were on at least one other medication that increased the prolactin levels. This included clomipramine, ranitidine, opiates such as oxycodone, and selective serotonin reuptake inhibitor agents such as sertraline and fluoxetine. Ten patients (17%) were on two or more antipsychotics. Oral risperidone or paliperidone depot (n = 17, 23.9%) was commonly used, both of which have a stronger effect on prolactin elevation compared to other atypical antipsychotics. Aripiprazole, which has a minimal effect on prolactin, was used in seven patients only (9.9%).

Of the 58 (84.1%) patients who were on antipsychotics, less than half (43.1%) had their prolactin levels checked. Mean prolactin levels in males and females were 22.4 and 10.1 ng/ml, respectively. Nine of the patients with their prolactin results had hyperprolactinemia (36%). All except one were males. Only two of the 16 who were admitted at least twice and only one patient on agents other than antipsychotics had their prolactin levels checked.

Reassuringly, none of the patients with hyperprolactinemia had levels more than 100 ng/ml, the threshold for intervention,[1] although in one patient, there had been a rapid increase from 30.2 to 91.7 ng/ml within 3 months.

Among patients with hyperprolactinemia, none had any significant radiological findings or hypothyroidism, although two had low estimated glomerular filtration rate.

Clinical symptom evaluation of hyperprolactinemia was not done in any patient with elevated prolactin. Out of the nine patients, three did not have any comments mentioning hyperprolactinemia in progress notes in CIMHA.

To the best of our knowledge, this is the first study to assess the level of hyperprolactinemia secondary to psychotropics in psychogeriatric population.

Previous work suggests that between 5% and 61% of patients, in general, are on more than one antipsychotic (except clozapine augmentation).[3] This is consistent with our finding in over-65s, which showed that 17% were on two or more antipsychotics with the consequent increased risk of hyperprolactinemia and associated pathological effects. Of concern is the high use of risperidone, a potent prolactin-raising agent, which is consistent with its indication in Australia for the management of behavioral and psychological symptoms in dementia, as well as mental illnesses such as schizophrenia in older populations.[4]

Our finding that only half the sample had prolactin levels checked despite a mean length of stay of 28 days suggests a lack of emphasis on screening for hyperprolactinemia.

Indeed, most attention has been on younger age groups where hyperprolactinemia is even more common at around 70.6% of in-patients (treated with both typical and/or atypical agents),[5] increasing to 72%–100% of females treated with risperidone.[6] Our study highlights that, although less common, this side effect also needs to be considered in older people, given that it was present in 38%.

There are several limitations to this study. We relied on routine documentation. While this would have captured the results of investigations, it might not have included any clinical examination that was performed but not recorded. The sample size was small and the number with hyperprolactinemia is insufficient to comment on any association with hypothyroidism, renal effect, and radiological findings.

We can conclude that active exploration and management of hyperprolactinemia is neglected in the treatment plan of mental illnesses in older persons. We recommend that prolactin levels are checked in all geriatric patients who are on prolactin-elevating agents, especially psychotropics, when they are admitted to mental health units.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.