Sequential pathway analysis of sex differences in deep brain stimulation for Parkinson's disease

ObjectivesDeep brain stimulation (DBS) is a well-established treatment for Parkinson's disease (PD). Despite its proven efficacy, women are less likely to receive DBS. This study examined sex differences across the multistage clinical pathway to identify stage-specific factors contributing to disparities in utilization.DesignRetrospective cohort study using longitudinal clinical data from a single, high-volume neurological care center.MethodsData were drawn from 4,308 patients with PD treated between 2012 and 2024. Progression through the DBS pathway was modeled as four conditional stages: (S1) referral, (S2) multidisciplinary evaluation among those referred, (S3) recommendation among those evaluated, and (S4) DBS surgery among those recommended. Stage-specific Firth penalized logistic regression models were used to estimate sex differences while adjusting for demographic and clinical characteristics, including age, race, comorbidities, marital status, levodopa use, and tremor status. Sex-by-predictor interactions were assessed to identify differential effects across stages.ResultsAmong the cohort (2,866 males, 1,442 females), 186 (4.3%) received a referral for evaluation; 180 (97%) received an evaluation; and 159 (88%) received DBS. Adjusting only for sex, compared to males, females were less likely to be referred (OR=0.97, CI=0.71, 1.32), evaluated given referral (OR=0.88, CI=0.1, 5.17), and receive DBS given recommendation (OR=0.61, CI=0.17, 2.38), but more likely to receive a recommendation after evaluation (OR = 1.55, CI = 0.59-4.70). Sex-Predictors odds ratios differed [male- S1: age (OR=0.95, CI=0.93, 0.97), comorbidities (OR=1.19, CI=1.00, 1.41); S2: comorbidities (OR=0.51, CI=0.20, 0.87); S3: age (OR=0.91, CI=0.84, 0.97), non-white (OR=0.29, CI=0.09, 0.88), comorbidities (OR=1.90, CI=1.09, 3.73); S4: non-white (OR=0.15, CI=0.02, 0.91); [females- S1: unmarried (OR=0.71, CI=0.38, 0.92); S2: levodopa (OR=1.24, CI=1.06, 1.90); S3: non-white (OR=0.01, CI=0.00, 0.31); S4: tremors (OR=1.55, CI=1.04, 1.87)].ConclusionStage-specific regression showed that differential characteristics were associated with sex disparities in DBS utilization, highlighting potential targets for equity interventions.