Selection of AVP-shortage patients as candidates for low-dose oral desmopressin administration

Abstract

AbstractIntroductionDiabetes insipidus (DI) is characterized by the excretion of large volumes of hypotonic urine and thirst due to an impaired ability to concentrate urine, leading to uncontrolled diuresis, which may cause life-threatening dehydration and electrolyte imbalances. Central DI is caused by the deficient secretion of the posterior pituitary antidiuretic hormone arginine vasopressin (AVP). Desmopressin (Deamino-8-D-AVP, the synthetic analogue of AVP, Minirinmelt®) is generally used to treat central DI. Desmopressin orally disintegrating tablets are recently administered to male patients with nocturia. We herein attempted to select male patients with an elevated nocturnal urinary frequency possibly due to a shortage of AVP. These patients may be good candidates for low-dose oral desmopressin administration.Patients and methodsSerum and spot urine osmolality, electrolytes, serum creatinine, casual blood glucose, plasma brain natriuretic polypeptide (BNP), and plasma AVP were measured at the same time in 97 elderly male patients with urinary symptoms under free water drinking. The International Prostate Symptom Score, Overactive Bladder Symptom Score, and frequency-volume charts at least twice were also evaluated.ResultsA binary plot of plasma AVP and serum osmolality indicated a region at which patients had relatively lower AVP considering higher serum osmolality. It was tentatively named the Desmopressin region. Twenty out of 97 (20.6 %) patients were in the Desmopressin region.No significant differences were observed in the frequency of administered urinary drugs or existing co-morbidities between patients in the Desmopressin and non-Desmopressin regions. Daily urine output did not exceed 3 L in any patient. Plasma AVP was lower, while serum osmolality and serum sodium were higher in patients in the Desmopressin region than in those in non-Desmopressin region. Furthermore, urine osmolality was slightly lower in patients in the Desmopressin region. No significant differences were observed in urine volume, urinary frequency, or urination questionnaire scores between both groups.ConclusionAVP-shortage patients may be selected for treatment with oral desmopressin based on measurements of serum osmolality and plasma AVP. After the exclusion of patients with marked hyperglycemia, decreased cardiac, or renal function, low-dose oral desmopressin may be administered to patients with an increased urine output, nocturia, elevated plasma osmolality, and relatively low plasma AVP.