in a U.K. cohort study.
Those are key findings from what is believed to be one of the largest studies to investigate fertility and obstetric outcomes in patients with psoriasis.
“Studies that have examined fertility and pregnancy outcomes in women with psoriasis have reported conflicting findings,” lead author Teng-Chou Chen, PhD, of the Centre for Pharmacoepidemiology and Drug Safety at the University of Manchester (England), and colleagues from the Global Psoriasis Atlas wrote in the study, published in JAMA Dermatology. Most of the studies were small, with under 100 women, “and are thus likely underpowered to detect a difference in pregnancy outcomes. The majority of those studies used disease registry data or lacked a matched comparison group and hence were unable to estimate the association of fertility and adverse pregnancy outcomes in women with psoriasis when compared with the general population.”
To determine fertility rates and birth outcomes in female patients with psoriasis, compared with age- and practice-matched patients without psoriasis, the researchers evaluated EHR data from a large U.K. primary care database, the Clinical Practice Research Datalink GOLD, from 1998 to 2019. They limited the analysis to patients aged 15-44 years and used relevant codes from clinical consultations to identify those with psoriasis. Then, for each patient with psoriasis, the researchers selected five comparators without psoriasis from the same primary care practice and matched for year of birth.
Both sets of patients were followed from the index date to age 45 years, death, transfer out of practice, last date of data collection, or end of the study period (Dec. 31, 2019), whichever came first. Pregnancy records were extracted for both sets of patients, and birth outcomes were categorized as pregnancy loss, live birth, stillbirth, and preterm birth. Adverse pregnancy outcomes were also collected. Finally, Dr. Chen and colleagues used a negative binomial model to examine the association between psoriasis and the fertility rate, and they applied logistic regression to compare the association between psoriasis and obstetric outcomes.
The analysis included 63,681 patients with psoriasis and 318,405 comparators whose median age on the index date was 30 years and who were followed for a median of 4.1 years. Among patients with psoriasis, 5.1% met criteria for moderate to severe disease in the follow-up period. The researchers observed that, compared with their age- and practice-matched counterparts, patients with psoriasis were more likely to be current smokers, alcohol drinkers, or overweight on the index date. They were also more often diagnosed with diabetes, hypertension, inflammatory bowel disease, thyroid disorders, and respiratory diseases such as asthma and chronic obstructive pulmonary disease.
Fertility, birth outcomes
When they looked at fertility outcomes, the researchers found that, compared with their matched peers without psoriasis, those with psoriasis had higher rates of fertility (risk ratio, 1.30; 95% confidence interval, 1.27-1.33; P < .001). But after the researchers stratified patients based on psoriasis severity, those with moderate to severe disease had significantly lower rates of fertility (RR, 0.75; 95% CI, 0.69-0.83; P < .001), compared those who did not have psoriasis.
As for adverse birth outcomes, compared with their matched comparators, pregnancies in patients with psoriasis were less likely to end in a live birth (odds ratio, 0.91; 95% CI, 0.88-0.93; P < .001). They also had a higher risk of pregnancy loss (OR, 1.06; 95% CI, 1.03-1.10; P < .001), most during the first trimester, at a gestation period of under 91 days.
In addition to psoriasis, patients younger than age 20 (OR, 2.04; 95% CI, 1.94-2.15; P < .011) and those aged between 20 and 24 years (OR, 1.35; 95% CI, 1.31-1.40; P < .001) had a higher risk of pregnancy loss, compared with those aged between 25 and 34 years.
However, no increases in the risks of antenatal hemorrhage, preeclampsia, or gestational diabetes were observed in patients with psoriasis, and no statistically significant differences in the odds of stillbirth and preterm birth were found between patients with psoriasis and matched comparators who did not have psoriasis.
“The mechanism to link the higher risk of pregnancy loss in patients with psoriasis is not clear, but there might be potential explanations,” the researchers wrote. “Psoriasis is characterized by the increased activity of [interleukin]-17, IL-23, and tumor necrosis factor–alpha. Those proinflammatory cytokines may negatively affect the placenta and cause impaired fetal growth.”
They recommended that further studies “evaluate the effects of better management of psoriasis and close monitoring during pregnancy on pregnancy loss.” In particular, “patients with psoriasis were more likely to have comorbidities that may be related to poor pregnancy outcomes, and hence increased emphasis of managing comorbidities as part of the routine management plan is also warranted.”
Dr. Alexa B. Kimball
Asked to comment on the study, Alexa B. Kimball, MD, MPH, who has been involved with research on this topic, said that she and other investigators had observed some years ago that fertility rates for women with moderate to severe psoriasis might be lower than expected.
This trend was observed in some psoriasis registries, some pregnancy registries, and in clinical practice, Dr. Kimball, professor of dermatology at Harvard Medical School, Boston, said in an interview. “This study clearly demonstrates that lower fertility rates in the moderate to severe psoriasis population occurs and compels further exploration of the reason why.” The reasons could be biologic, she continued, including difficulty conceiving or an increased risk of miscarriage, sociobehavioral issues, or a combination.
“Behavioral examples could include that some women with moderate to severe psoriasis can flare during pregnancy, which might affect their choice” to become pregnant, Dr. Kimball said. “Stigma may also play a role in how women with moderate to severe psoriasis form relationships. Now that there are much better treatments for moderate to severe psoriasis and better knowledge about managing psoriasis during pregnancy, it will also be important to explore whether these trends change over time.”
The study was funded by the International League of Dermatological Societies on behalf of the Global Psoriasis Atlas. Two of the study authors reported receiving consulting fees and grant support from many pharmaceutical companies. Dr. Kimball disclosed that she serves or has served on several Organization of Teratology Information Specialists advisory board pregnancy registries, is a consultant and investigator for Abbvie, Janssen, Lilly, Bristol-Myers Squibb, Moonlake, UCB, and Amgen; has fellowship funding from Janssen; and serves on the board of Almirall.