Women with Parkinson’s less likely to be referred for DBS than men

40% of patients are women, but that doesn't fully explain access disparity

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by Andrea Lobo |

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Women with Parkinson’s disease are less likely to be referred for deep brain stimulation (DBS) evaluation than men, a study has found.

Moreover, women with essential tremor, a disease that shares symptoms with Parkinson’s and can also be treated with DBS, were more likely to decline surgery, once approved.

Although further studies are needed to better understand these gender differences in accessing DBS,  “women often have less support than men and less access to caregivers, so additional interventions, such as setting up home health after surgery, may be helpful,” the researchers wrote in “Gender Disparities in Deep Brain Stimulation Surgery for Parkinson Disease and Essential Tremor,” which was published in Deep Brain Stimulation.

Used for treating motor symptoms such as tremors, rigidity, stiffness, and slowed movements in people with Parkinson’s disease, DBS, which involves implanting a device that stimulates key brain regions with electrical impulses generated by a neurostimulator, has been shown to be effective for Parkinson’s and essential tremor patients who don’t respond well to medication.

Although 40% of people with Parkinson’s are women, only 23-30% of DBS surgeries are performed in women. This is particularly concerning given that women report a lower quality of life and higher disease-related disability than men.

While lower disease prevalence might be part of the reason women are less likely to access DBS, it doesn’t fully explain the discrepancy, leading researchers in the U.S. to use a national population-based dataset – the National Readmissions Database, part of the Healthcare Cost and Utilization Project — and local clinical data from the University of Colorado DBS program to determine why there is a gender disparity among Parkinson’s and essential tremor patients.

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The long journey to my husband’s deep brain stimulation surgery

Nationwide, local clinical data highlight disparities in accessing DBS

The nationwide data identified 6,952 people with Parkinson’s disease who underwent DBS in the U.S. from 2016-2017. Of them, 2,117 were women (30.5%) and 4,835 were men (69.5%). Women had significantly higher rates of electrolyte disturbances (23.7% vs 19.3%) and hypothyroidism (low production of thyroid hormones, 19.2% vs 7.2%) than men.

They were also significantly more likely to have Medicare (69.8% vs 64.2%) and Medicaid (2.3% vs 1.8%) insurance, while men were more likely to have private insurance. No differences regarding age, income, total charges, longer hospital stays, or hospital characteristics were found.

One-third of DBS surgeries were performed in Parkinson’s patients 70 years or older, 30% of whom were women.

Nationwide data identified 3,000 essential tremor patients who underwent DBS — 42.6% were women. Moreover, women comprised 44% of those 70 or older treated with DBS for essential tremors.

No gender differences were found in patient age, income, total charges, or hospital characteristics. Women had significantly longer hospital stays than men, however.

In the local clinical data, 428 people (mean age, 63.8; 30.6% women) with Parkinson’s were referred to DBS evaluation between January 2011 and December 2020, 326 of whom (76.2%) completed the evaluation. Women had significantly longer disease duration than men at the time of evaluation (8.6 vs. 7.4 years).

During this period, 7,170 people with Parkinson’s had at least one neurology visit at the University of Colorado — 38% were women.

“The proportion of women referred for DBS was significantly lower than expected given the demographics of the PD patients seen in the Neurology clinic,” the researchers wrote.

Of the 326 patients who completed the full evaluation, 274 were approved for surgery. Of the 251 who accepted, 71 (28.6%) were women. “There were no gender differences in the proportion of patients who completed the evaluation, were approved for surgery and accepted surgery once approved,” the researchers wrote.

Only 8.2% of men and 9.0% of women declined surgery once approved, usually due to concerns about surgical risks, not feeling ready for surgery, or a desire to try more conservative treatments.

Women with essential tremor more likely to decline DBS

Regarding essential tremor, 126 patients were referred for DBS, of whom 90 completed the full evaluation and 66 were approved for surgery. Of the 53 patients who accepted surgery, 13 (24.5%) were women.

Among those approved for surgery, women were significantly more likely than men to decline it (35% vs. 13%), suggesting “women may be more reluctant to undergo surgery due to perceived risks and less social support, both barriers that contribute to lower DBS utilization,” the researchers wrote. “This disparity is problematic, as women may be missing out on an effective treatment that is proven to improve quality of life.”

While the reasons for the gender discrepancy for accessing DBS surgery remain unclear, the researchers suggested healthcare providers might be less likely to refer women or assume they wouldn’t want surgical procedures, women may be more risk-averse or not be able to forego caregiving roles to have surgery, or there might be differences in when and how advanced treatment options are discussed with women.

They said studies should address patient knowledge and attitudes toward DBS to better understand why these discrepancies exist and interventions should be developed to eliminate barriers to effective care.