The study, led by Joseph McGrath and Evelyn Fagan Burley, with senior authorship from Sarah Lonowski and Kaleb Michaud at the University of Nebraska Medical Center, set out to assess representation in the FORWARD registry, a nation-wide, patient-reported psoriasis and psoriatic arthritis registry. The team’s approach was deliberately grounded: rather than comparing FORWARD against census data or other registries, they compared it against the electronic medical record of a single academic institution, using that clinic population as a benchmark for the kinds of patients who seek care for psoriasis in a real-world setting. The work was approved under institutional review board protocol 0770-24-EP, and the authors report no funding and no conflicts of interest.

FORWARD is not a small or casual undertaking. Described in a 2024 paper in the Journal of Psoriasis and Psoriatic Arthritis, it is a novel registry built around patient-reported outcomes, collecting longitudinal data directly from people living with psoriasis and psoriatic arthritis across the country. Patient-reported outcome registries occupy an important niche in dermatology because many of the outcomes that matter most to patients, such as itch, fatigue, skin-related stigma, and functional impairment, are poorly captured by routine clinical documentation. By asking patients directly and repeatedly over time, FORWARD can track disease trajectories in a way that claims data or chart reviews cannot.

Yet the very design that gives such registries their power also introduces a structural vulnerability. Enrollment in FORWARD is voluntary and, like many contemporary registries, it relies heavily on digital infrastructure for recruitment and follow-up. A well-documented body of research, including a 2019 analysis in the Journal of the American Medical Informatics Association by Toscos and colleagues, has shown that technology-based research participation is not demographically neutral: patients who sign up for app-based or web-based studies tend to differ systematically from those who do not, in ways that track both socioeconomic status and health status. If those selection pressures operate within FORWARD, the registry’s findings could quietly drift away from the broader psoriasis population it is meant to represent.

This is the concern that motivated the single-institution comparison. Registry science in dermatology has wrestled with questions of validity for more than a decade. A 2017 commentary in the British Journal of Dermatology by Egeberg and Nast urged a critical eye on registry data in psoriasis, and a 2011 systematic review in BMC Medical Research Methodology by Langham and colleagues found that large prospective observational studies in psoriasis and psoriatic arthritis varied widely in quality and in how transparently they reported potential biases. A 2016 review of patient registries in dermatology by DiMarco, Hill, and Feldman in the Journal of the American Academy of Dermatology similarly catalogued the methodological trade-offs inherent in registry design. Against that backdrop, the Nebraska team’s audit is less an indictment than a routine but essential quality check, the epidemiological equivalent of calibrating an instrument before trusting its readings.

The logic of the comparison deserves unpacking, because it illustrates a core technique in registry validation. When researchers want to know whether a national registry is representative, they need an external reference population. Census data offer demographics but no clinical detail; claims databases offer clinical breadth but shallow phenotyping. A single academic institution’s electronic medical record, by contrast, provides a richly characterized cohort of diagnosed psoriasis patients with documented demographics, comorbidities, and treatment histories. By comparing the characteristics of FORWARD enrollees against eligible patients at the institution, the researchers could identify dimensions along which the registry over- or under-represents the clinical population, whether by age, sex, disease severity, psoriatic arthritis status, or treatment intensity.

Why does this matter so much for psoriasis specifically? Psoriasis is a chronic immune-mediated disease affecting roughly two to three percent of many adult populations, and its management has been transformed over the past two decades by biologics and targeted oral therapies. Decisions about which patients should escalate to expensive systemic therapy, how to weigh cardiovascular and metabolic comorbidity in treatment planning, and how to monitor long-term drug safety all draw heavily on observational evidence. If registry cohorts skew toward younger, more digitally connected, more engaged patients, then estimates of treatment effectiveness, adverse event rates, and comorbidity burden may not transfer cleanly to older patients, those with limited internet access, or those managed outside specialty centers. Generalizability, in other words, is not an abstract statistical virtue; it determines whose care is guided by the evidence.

The study also speaks to a broader and increasingly urgent conversation about equity in data-driven medicine. Registries feed algorithms, guidelines, and policy, and any systematic under-representation within them propagates silently into those downstream products. The authors’ decision to test representation using a concrete, verifiable comparator, rather than simply asserting generalizability, models a practice that other registry-based fields would do well to emulate. It also highlights the distinctive value of academic medical centers as audit points: their patient populations are themselves imperfect samples of the general population, but they are transparent, documentable samples, which makes them useful yardsticks even with their own known biases.

It is worth emphasizing what this research letter does not claim. A single-institution comparison cannot, by itself, establish how representative FORWARD is of the entire United States psoriasis population, and the authors present their work as an assessment rather than a definitive verdict. The data underlying the comparison were drawn from the institution’s electronic medical record under IRB oversight and were deliberately not made publicly available, in order to protect patient confidentiality, a constraint that reflects the tension between methodological transparency and privacy in clinical data research. The letter’s contribution lies in its method and its framing: it demonstrates that representation audits are feasible, inexpensive, and informative, and it invites similar checks at other institutions to build a fuller picture of where the registry aligns with clinical reality and where it diverges.

For clinicians and patients, the practical takeaway is one of informed confidence. FORWARD remains a vital resource, and the fact that its stewards, including Michaud, a veteran registry scientist best known for decades of work on rheumatology registries, subjected their own cohort to external scrutiny is a mark of methodological seriousness rather than weakness. The study, published as volume 318, article 423 of the Archives of Dermatological Research, arrives at a moment when real-world evidence is being asked to carry more weight than ever in dermatology. Ensuring that the patients inside the database resemble the patients in the exam room is the unglamorous, foundational work on which everything else, from drug safety signals to treatment guidelines, ultimately depends. As registries grow larger and more influential, expect more studies of this kind, quietly checking the mirror to make sure it reflects everyone it claims to.

Subject of Research: Evaluation of demographic and clinical representation in the FORWARD national psoriasis registry using a single-institution electronic medical record comparison

Article Title: Assessing representation in a nation-wide psoriasis registry: a single-institution comparison

Article References: McGrath, J., Burley, E. F., Sullivan, C., Kilton, M., Michaud, K., & Lonowski, S. (2026). Assessing representation in a nation-wide psoriasis registry: a single-institution comparison. Archives of Dermatological Research, 318(1), Article 423. https://doi.org/10.1007/s00403-026-04860-9

Image Credits: AI Generated

DOI: 10.1007/s00403-026-04860-9

Keywords: FORWARD registry, psoriasis, psoriatic arthritis, patient registries, representation, generalizability, selection bias, patient-reported outcomes, dermatology, electronic medical records, real-world evidence, registry methodology

The study, led by Walter E. Kaufmann of the Department of Human Genetics at Emory University School of Medicine and Paul S. Horn of the Division of Neurology at Cincinnati Children’s Hospital Medical Center, together with the FORWARD Consortium, drew on the pediatric FORWARD database, a multi-site registry and longitudinal clinical database established to study fragile X syndrome across specialty clinics in the United States. The analytical sample comprised 1,072 males and 338 females, an unusually large cohort for a rare genetic disorder, allowing the researchers to examine patterns of co-occurrence with a statistical power that smaller, single-center studies could not achieve.

The team focused on the eight most common behavioral comorbidities identified by clinicians in these specialty fragile X clinics: attention problems, anxiety, hyperactivity, autism spectrum disorder, mood disturbances, irritability and aggression, self-injurious behavior, and sleep problems. Importantly, the researchers treated these as clinician-identified behavioral concerns rather than formal diagnoses, with one exception. Autism spectrum disorder was the only comorbidity defined using explicit DSM-5 criteria, reflecting the particular diagnostic challenges that autism presents in fragile X syndrome, where the social and repetitive features of the syndrome itself can blur the boundary between behavioral phenotype and co-occurring condition.

Across the cohort, attention problems and anxiety emerged as the two most frequent behavioral comorbidities, and, notably, also as the mildest in terms of functional impact. By contrast, the cluster of disruptive behaviors captured under the umbrella of irritability, aggression, agitation, and self-injurious behavior, while less universally present, carried substantially greater weight in terms of impairment. Roughly half of the children affected by any given behavioral comorbidity showed functional impairment from that condition, a proportion that underscores how often these difficulties cross the threshold from trait to clinically meaningful problem in fragile X syndrome.

The most striking finding concerned co-occurrence. Among children with fragile X syndrome, 69 percent were reported to have impairing behavioral comorbidities occurring together, and 39 percent of those children presented with more than two comorbidities simultaneously. Children with multiple co-occurring conditions showed the greatest overall impairment, a dose-response-like pattern suggesting that the cumulative behavioral load, rather than any single diagnosis, is what most powerfully determines how much a child’s daily functioning is compromised. For families and clinicians, this finding reframes fragile X syndrome not as a condition with one dominant behavioral complication but as one in which multiple behavioral challenges frequently compound one another.

To dissect these patterns, the researchers deployed an unusually rich statistical toolkit. Chi-square analyses quantified how frequently pairs of comorbidities appeared together. Polychoric and polyserial correlations, methods designed to estimate the association between ordinal and continuous variables that underlie observed categorical ratings, allowed the team to measure the strength of association between comorbidities while correcting for the fact that co-occurrence is partly driven by simple frequency. Mann-Whitney tests compared behavioral scale scores between groups. This distinction between frequency-driven co-occurrence and genuine statistical association proved crucial: the researchers found that while which comorbidities co-occur is influenced by how common each one is, the strength of the association between any pair was relatively independent of frequency, implying that some pairings reflect shared underlying mechanisms rather than mere arithmetic.

Two of those strong associations stood out because they replicate well-documented patterns in the general, non-fragile X population. The first was the pairing of attention problems with hyperactivity, a combination familiar from attention deficit-hyperactivity disorder in typical development. The second was the coupling of anxiety with mood disturbances, echoing the extensive literature on comorbidity between anxiety and mood disorders in the general psychiatric population. That these canonical pairings also hold in fragile X syndrome suggests that at least some of the architecture of behavioral comorbidity in this genetic condition mirrors the structure seen in the broader population, even though the underlying biology is profoundly different.

The team also examined how standardized behavioral scale scores related to the clinician-identified comorbidities. Scale scores broadly aligned with other severity parameters, lending convergent validity to the clinician-based classification. However, correlations between comorbidities and specific scales tracked the relevance of the behaviors each scale evaluates, rather than behaving as simple proxies for severity. In other words, a given scale correlated most strongly with the comorbidities whose symptom content it directly captures, a finding that helps clinicians interpret behavioral checklist data in fragile X syndrome with appropriate nuance.

Perhaps the most unexpected result of the entire analysis was the discovery that all eight behavioral comorbidities were strongly correlated with the Sensory problems scale. Sensory difficulties, including hyperarousal to sound, touch, and visual stimuli, have been increasingly recognized as central features of fragile X syndrome, with prior work from the FORWARD registry documenting their prevalence and their links to hyperarousal. But the uniformity of the association across such clinically distinct comorbidities, from attention deficits to aggression to sleep disturbance, was not anticipated. The finding raises the possibility that sensory dysregulation functions as a transdiagnostic factor in fragile X syndrome, a common physiological substrate that feeds into or amplifies virtually every major behavioral problem the condition produces. If confirmed by future longitudinal work, this would carry direct therapeutic implications: interventions targeting sensory hypersensitivity and hyperarousal might yield benefits across a wide swath of behavioral comorbidities simultaneously, rather than requiring separate treatments for each condition.

The authors caution that their data are cross-sectional and clinic-based, drawn from children evaluated at specialty fragile X clinics and therefore not necessarily representative of the full population spectrum of the disorder, which includes individuals with milder presentations never referred to specialty care. Even so, the scale of the FORWARD database and the consistency of the findings give the profiles considerable weight. The research team suggests that the reported profiles of impairing behavioral comorbidities could assist clinicians in the early identification of behavioral symptoms in children with fragile X syndrome and in refining the management of those symptoms, and, they add, perhaps in other neurodevelopmental disorders as well, where multi-comorbidity burdens are similarly common and similarly under-characterized. The study was supported by cooperative agreements and a contract funded by the Centers for Disease Control and Prevention, and de-identified data from the FORWARD project are available under the project’s data sharing plan and CDC policies, opening the door for further analyses of how these behavioral trajectories unfold over time.

Subject of Research: Behavioral comorbidities and their co-occurrence patterns in children with fragile X syndrome

Article Title: Profile of Behavioral Comorbidities in Children With Fragile X Syndrome

Article References: Kaufmann, W. E., Horn, P. S., FORWARD Consortium, Berry-Kravis, E., Velinov, M., Talboy, A. L., Sherman, S. L., Kaufmann, W. E., Schuster, M., Tartaglia, N., Filipink, R. A., Budimirovic, D. B., Barbouth, D., Lightbody, A., Reiss, A., Delahunty, C. M., Hagerman, R. J., Hessl, D., Erickson, C. A., … Morris, S. M. (2026). Profile of Behavioral Comorbidities in Children With Fragile X Syndrome. Journal of Autism and Developmental Disorders. https://doi.org/10.1007/s10803-026-07525-8

Image Credits: AI Generated

DOI: 10.1007/s10803-026-07525-8

Keywords: fragile X syndrome, behavioral comorbidities, anxiety, attention problems, autism spectrum disorder, sensory problems, FORWARD registry, intellectual disability, hyperactivity, self-injurious behavior, neurodevelopmental disorders, FMR1