Nineteen studies (n=743 patients, range two to 221) were included.
The proportion of patients with persistent normoprolactinaemia after withdrawal of dopamine agonists ranged from zero to 74%. The pooled proportion, using a random-effects model, was 21% (95% CI 14 to 30; 19 studies), although heterogeneity was high (I2=81%).
A number of sensitivity analyses were performed. For the type of dopamine agonist, pooled proportions were 35% (95% CI 19 to 56; four studies; I2=85%) for cabergoline and 20% (95% CI 14 to 28; 12 studies; I2=20%) for bromocriptine. Studies of idiopathic hyperprolactinaemia had more treatment success (32%, 95% CI 5 to 80; three studies; I2=85%) compared with microprolactinomas (21%, 95% CI 10 to 37; 13 studies; I2=84%) and macroprolactinomas (16%, 95% CI 7 to 36; eight studies; I2=68%). Higher rates of persisting normoprolactinaemia were also seen in studies of more than 24 months duration (34%, 95% CI 19 to 52; seven studies; I2=91%) compared with shorter studies (16%, 95% CI 11 to 22; 12 studies; I2=0%).
Meta-regression showed that, after adjusting for the cause of hyperprolactinaemia, a longer treatment duration was associated with a higher proportion of persisting normoprolactinaemia (p=0.015).