乌鸦传媒

BARCELONA -- Patients with multiple sclerosis are at a higher risk of suicide, as well as suicide attempts and other types of self-harm, compared with the general population, according to findings from two registry studies here.

In a large Swedish registry study, MS patients were at twice the risk of completing a suicide than the general population adjusted (HR 1.87, 95% CI 1.53-2.30), according to Philip Brenner, MD, of Sweden's Karolinska Institute in Stockholm.

They also attempted suicide at more than twice the rate compared with healthy controls, Brenner reported (adjusted HR 2.18, 95% CI 1.97-2.43).

A separate British registry study found that the risk of any type of self-harm was higher by almost 60% in MS patients compared with the general population according to , of the health economics research firm Evidera, and colleagues.

Both studies were reported here at the annual meeting.

In his platform presentation, Brenner noted that several previous studies had examined rates of completed suicide and had shown convincingly that they were significantly higher among MS patients than would be expected for their age, socioeconomic status, and other factors. But broader measures of suicidality and intentional self-harm had not been so well examined.

Attempted suicides, for example, had only been addressed in two earlier studies, he said. One was reported in 1998 and showed that, indeed, attempted suicides were about three times as common in MS patients relative to controls. But another more recent study in Denmark failed to find a significant increase (although Brenner said, that with only 404 patients, it may have been underpowered).

For his study in Sweden, he and colleagues pulled data from the nation's comprehensive health registry systems. Each of the 29,617 MS patients identified was matched on the basis of birth year, sex, and county of residence at the time of MS diagnosis from a pool of 300,000 healthy controls. Also, census data provided educational attainment for patients and controls.

The results confirmed a nearly doubled risk of completed suicide among the patients (adjusted HR 1.87, 95% CI 1.53-2.30). And it also supported the investigators' hypothesis that suicide attempts (measured via ICD-7/8/9/10 codes for self-poisoning and intentional self-injury) were increased as well at a similar magnitude.

Attempts were seen at a rate of about 116 per 100,000 population among MS patients, compared with 50.8 per 100,000 among controls.

Subgroup analyses, though, provided some interesting findings and questions for future research, Brenner indicated. For example, attempts were more common -- by about 30% -- among female versus male MS patients, and among female versus male controls as well. Increased educational attainment tended to decrease the risk of suicide attempts in both patients and controls.

He also noted that excluding patients with a history of suicide attempts prior to MS diagnosis did not change any of the patterns seen in the primary analyses.

A different picture emerged when completed suicides were considered. Rates were markedly lower among female versus male patients (ratio 0.38), and higher educational attainment did not reduce the risk of completed suicide among patients, whereas it did among controls.

Brenner speculated that, among patients, the "adverse life events" that come with MS hit the educated just as hard as those with less education and make them just as likely to commit suicide.

But he said that clinical details (such as type of MS and medication history) were lacking in the registry data and that this was a noteworthy limitation.

The study by Ramagopalan and colleagues had a roughly similar design: it examined hospitalization and death registry data covering some 50 million people in England from 1999 to 2011. Included were some 82,000 individuals with a diagnosis of MS who had been hospitalized during the period, along with a control population of about 9.1 million who had been seen in hospitals for other "mainly minor" conditions such as ingrown toenail or otitis externa.

Every subgroup the researchers analyzed -- by gender, age at admission, and time since MS diagnosis -- showed an increased risk of self-harm among MS patients versus controls. The same was true for completed suicides, for which the relative risk overall was 1.86 (95% CI 1.37-2.47), nearly identical to the rate seen in the Swedish study.

The British researchers noted that they, too, lacked data on specific MS types or other characteristics, and also that reliance on hospital records limited the study's applicability to patients whose conditions never warranted hospitalization.