Early constipation portends progression to dementia in Parkinson’s disease patients

In individuals recently diagnosed with Parkinson’s disease (PD), the presence and severity of constipation may be indicative of subsequent progression to dementia, a study has found.

The analysis used data from the Parkinson’s Incidence Cohorts Collaboration (PICC) and included 465 patients diagnosed with idiopathic PD. Of these, 97 patients (20.9 percent) had ‘minor’ constipation, 55 (11.8 percent) had ‘major’ constipation, and 313 (67.3 percent) did not report any constipation (control) at baseline.

Compared with those in the minor constipation and control groups, patients with major constipation had higher baseline Movement Disorders Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS-III) scores (p<0.01). Hoehn and Yahr (H&Y) stage and age were also higher in the major than the control group.

Over 8 years of follow-up (average 5.1 years) from PD diagnosis, dementia, postural instability, and death occurred more rapidly in patients with more severe constipation at baseline (Kaplan–Meier survival analysis).

The mean time to dementia was 6.0 years in the major constipation group, 7.1 years in the minor constipation group, and 7.5 years in the control group. The corresponding mean time to developing H&Y score ≥3 and death was 5.5 and 8.7 years in the major constipation group, 6.4 and 9.7 years in the minor constipation group, and 6.9 and 10.0 years in the control group.

Multivariable Cox regression analysis confirmed a significant relationship between constipation severity and progression to dementia (hazard ratio, 1.45; p=0.008) but not postural instability or death.

The findings suggest that early constipation and associated translocation of bacterial products into the circulation may play an important role in cognitive decline in PD.