DBS may prolong Parkinson’s survival
medwireNews: Patients with Parkinson’s disease (PD) who undergo deep-brain stimulation (DBS) of the subthalamic nucleus (STN) have better survival rates that those who opt to continue with medical therapy, shows a 10-year study.
Moreover, among 147 patients offered STN-DBS, just 6% of 106 patients who underwent the procedure were admitted to residential care during the study period, compared with 37% of 41 who chose to remain on medical therapy, and this difference remained significant after accounting for confounders.
Over the 10 years of follow-up, 17.0% of patients who underwent STN-DBS died, compared with 41.5% of patients on medical therapy, equating to a 71% reduced risk after adjusting for confounders.
“Improved survival is not usually among the benefits cited when discussing the option of undergoing STN-DBS with patients suffering from severe PD,” comment lead researcher Desire Ngoga (The University of Birmingham, UK) and colleagues.
They therefore believe that their findings “warrant further investigation among larger patient cohorts, recognising that randomised comparisons may no longer be feasible.”
Although not randomized, the two groups under study were well matched at baseline for factors including age, gender, duration of disease, medication dose, and rate of depression.
“We considered the possibility that patients declining surgery may have had more severe PD and either consciously or unconsciously clinicians or patients were more apprehensive about surgery,” write the researchers in the Journal of Neurology, Neurosurgery & Psychiatry.
But, in fact, they found that more patients in the STN-DBS group were taking apomorphine at baseline, implying that they may have had slightly worse symptoms than those in the medical therapy group.
The researchers believe that a reduced risk for aspiration pneumonia may underlie the improved survival seen with STN-DBS. Patients in this group had a broad range of causes of death, with just 2% dying of respiratory causes, whereas eight (20%) patients in the medical therapy group had respiratory causes of death; seven of these patients died of pneumonia, which was attributed to aspiration on the death certificates of three.
Studies have shown improved oropharyngeal phase of swallowing in patients under STN stimulation, note Ngoga et al.
They suggest: “This may offer a possible mechanism for the improved survival among surgical patients since possible improvements in the oropharyngeal phase of deglutition may reduce the risk of aspiration pneumonia in patients undergoing STN-DBS.”
medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013
By Eleanor McDermid, Senior medwireNews Reporter