Atopic dermatitis in the French cohort CONSTANCES (PreDDA study): Focus on persistence and remission in adulthood

Abstract

Atopic dermatitis (AD) prevalence has been increasing over the past 20 years, affecting infants but also occurring or persisting into adulthood.¹ The main objective of the PreDDA study was to estimate adult prevalence of AD in a French representative population-based cohort of adults (CONSTANCES),² and to describe factors associated with different profiles of AD.

CONSTANCES was used to select, among 99,103 participants who responded to a questionnaire sent in 2018 (Q₂₀₁₈) (62.4% of 158,898), the 10,950 participants who answered positively dedicated questions to screen probable AD during a lifetime,³ regardless of current persistence or age of onset. In 2022, a questionnaire (Q₂₀₂₂) was sent to the latter to collect AD characteristics and their impact on quality of life. Subsequently, 84.3% of the 6132 respondents (N = 5172) confirmed their AD (AD+). They reported that the diagnosis had been made mainly by dermatologists (38.7%) or attending physicians (31.8%), but 5.9% by themselves, whereas 8% ‘didn't know’. They were asked if their AD was still present: 49.0% (N = 2533) declared an inactive AD (ADi) and 45.6% (N = 2358) an active AD (ADa) (Table 1). Among ADa participants, 43.4% rated the severity of their current episode as mild, 41.6% as moderate and 15.0% as severe. The most common locations of these episodes were hands/fingers (42.0%) and scalp (36.0%). Quality of life (QoL) was assessed with the DLQI score⁴: only 5.0% of ADa participants declared that their AD had no effect on their QoL, compared to 23.3% in another French study.⁵ This previous study reported that, according to the ADCT score,⁶ AD was not controlled for 71.4% of patients,⁵ compared to 43.6% of ADa participants in PreDDA.

The proportion of the French population having AD was estimated at 9.1%–9.5% (accounting for 44.0% non-response to Q₂₀₂₂ and 15.7% who no longer reported AD in 2022, with a 30% variation coefficient), which is double the prevalence previously estimated (4.7%).⁸ More precisely, 2.1%–2.6% were estimated to have an AD that started in adulthood, 2.5%–2.9% an AD that started before adulthood and persisted after, and 3.1%–3.5% that did not persist.

Q₂₀₂₂ responders were matched 1:1 by age and sex with 6132 controls without AD history reported in Q₂₀₁₈ (AD−). Compared to AD− and ADi, ADa participants had higher education (p < 0.001) and socio-economic status (p = 0.002), were more likely to report depressive symptoms (CES-D score⁹ ≥16, p < 0.001), be on a diet (p < 0.001), and rate their health as poor (p < 0.001). ADa and ADi participants had higher prevalences of pulmonary diseases (p < 0.001), neuropsychological and neuropsychiatric disorders (p < 0.001 for both), sleep disorders (p = 0.043), metabolic disorders (p = 0.043), liver diseases (p = 0.025) and associated dermatological conditions (p < 0.001). In addition, 41.9% of AD+ participants had a first-degree relative with AD, with a higher percentage for ADa than for ADi participants (p < 0.001).

A linkage with the national medico-administrative database (SNDS) was performed to collect detailed healthcare resource utilization data between 2019 and 2021 (Table 2). As expected, according to current treatment guidelines in France,¹⁰ ADa participants, compared to AD− and ADi, had significantly higher visits to general practitioners (p < 0.001) and dermatologists (p < 0.001), higher deliveries of dermatological drugs (p < 0.001), topical corticosteroids (p < 0.001) and phototherapy sessions (p = 0.009). Similarly, a higher proportion received topical corticosteroids, systemic immunosuppressants or immunomodulators and tacrolimus (all p < 0.001). Conversely, fewer participants received azathioprine (p = 0.021) or methotrexate (p = 0.004) despite them being second- and third-line treatments.¹⁰

This study provided an initial overview of AD in France, with a significant degree of precision and detail. The main limitation is that the confirmation of the diagnosis was not collected directly from the physician. Nevertheless, PreDDA could be used to perform additional analyses to better understand the characteristics associated with certain sub-populations of interest.

The CONSTANCES cohort study was supported and funded by the French National Health Insurance Fund (‘Caisse nationale d'assurance maladie’, Cnam). Constances is a National infrastructure for biology and health (‘Infrastructure nationale en biologie et santé’) and benefits from a grant from the French National Agency for Research (ANR-11-INBS-0002). CONSTANCES is also partly funded to a small extent by industrial companies, notably in the healthcare sector, within the framework of Public-Private Partnerships (PPP). The PreDDA project was funded by L'Oréal, which took part in the design of the study.

KE is a consultant for AbbVie, Incyte, La Roche-Posay, Pfizer, Pierre Fabre, Sanofi and BMS. AN is a consultant for L'Oréal, Avene and Naos. MZ, SK, AR and MG have no conflict of interest. VH and SC are employed by L'Oréal. FR, AZ and AS are employed by ClinSearch.

CONSTANCES received approvals from the Ethics Evaluation Committee of the French National Institute of Health and Medical Research and from the French National Committee for the Protection of Privacy and Civil Liberties. PreDDA received approvals from the International Scientific Committee of CONSTANCES and the CONSTANCES team. The study was conducted in accordance with French regulations and followed the principles of the Helsinki Declaration.

All the participants provided informed consent.