Determinants of stimulated salivary flow among haematopoietic stem cell transplantation recipients

The aetiology of hyposalivation in haematopoietic stem cell transplantation (HSCT) recipients is not fully understood. This study examined the effects of treatment-related aetiological factors, particularly medications, on stimulated salivary flow in HSCT recipients. Adult HSCT recipients (N = 118, 66 males, 27 autologous and 91 allogeneic transplants) were examined. Stimulated whole salivary flow rates (SWSFR) were measured before HSCT and at 6 and 12 months post-HSCT. Linear regression models were used to analyse the associations of medications and transplant-related factors with salivary flow rates, which were compared to salivary flow rates of generally healthy controls (N = 247). The SWSFR of recipients were lower pre-HSCT (mean +/- standard deviation, 0.88 +/- 0.56 ml/min; P <0.001), 6 months post-HSCT (0.84 +/- 0.61; P <0.001) and 12 months post-HSCT (1.08 +/- 0.67; P = 0.005) than the SWSFR of controls (1.31 +/- 0.65). In addition, hyposalivation (<0.7 ml/min) was more frequent among HSCT recipients pre-HSCT (P <0.001), 6 months post-HSCT (P <0.001) and 12 months post-HSCT (P = 0.01) than among controls. The SWSFR was observed to improve over time being significantly higher 12 months post-HSCT compared to pre-HSCT (P <0.001). The observed decrease of salivary flow could not be explained by the examined transplant-related factors and medications. Decreased stimulated salivary flow rates could not be explained by the examined factors alone; these findings indicate that hyposalivation in HSCT recipients exhibits a multifactorial aetiology. All HSCT recipients should be considered to be at high risk of hyposalivation and consequent oral diseases, and they should be treated accordingly.Peer reviewe