People who are controlling their rheumatoid arthritis (RA) with an anti-tumor necrosis factor (anti-TNF) drug may get sicker if they switch to a different one, researchers say.

The finding shows the problems that could arise for people who can’t afford their current medication because they leave a job or change insurance plans, said Martha Skup, PhD, a researcher at AbbVie in North Chicago.

She and her colleagues called changing medications for these sorts of reasons “non-medical switching.”

Martha Skup, PhD, health economics and outcomes researcher, AbbVie

Martha Skup, PhD, health economics and outcomes researcher, AbbVie

Anti-TNF drugs are a class of drugs that treat inflammatory conditions such as RA. They include Remicade, Enbrel, Humira, Simponi and Simponi Aria. These drugs are often able to reduce inflammation and stop disease progression.

Dr. Skup and her colleagues identified 166 patients with RA whose physicians had reported them as being stable on anti-TNFs for six or more months.

The researchers divvied these patients into 83 pairs, with each pair having one patient who switched or discontinued their use of anti-TNF due to non-medical reasons and one patient who remained on the same drug. Both patients in each pair were being seen by the same rheumatologist.

If a patient switched or discontinued use of the treatment, the researchers traced the health for both people in the pair for 12 months.

When looking at characteristics of the groups at the start of the study, the researchers noted that 23 percent of those who switched or discontinued were Hispanic compared to only 13 percent of those who continued.

But there was no difference in symptoms or other major attributes between those who switched and those who didn’t before the switch. About half were white, a quarter male and 10 percent black.

Fifty-nine percent of the people who switched and 47 percent of those who did not switch reported mild symptoms. About a third of both groups were taking Humira, a third taking Enbrel and 16 percent taking infiximab (Remicade, Remsima, Inflectra), with the rest taking Cimzia or Simponi. Many were taking other drugs as well.

But a year after half these pairs switched their anti-TNF drugs, changes emerged, says Skup. “The main conclusion is that patients who switched anit-TNFs experienced adverse outcomes compared with patients who continued.”

Only 48 percent of those who switched had well-controlled disease symptoms reported by the rheumatologist compared to 84 percent of those who did not switch.

Also the patients who switched or discontinued were almost 4 times more likely to have a disease flare and 10 times more likely to visit the emergency room. And they were more likely to stay overnight in a hospital.

The hospital visits may have imposed some additional costs on whoever paid the medical bills of patients who switched anti-TNF drugs for non-medical reasons.

There’s a message here for anyone who influences the medication choices of people with RA, said Skup: “Don’t mess with the ones who are stable.”

The study was financed by AbbVie.