Alopecia Areata
Conditions
Brief summary
Alopecia areata (AA) is a common immune-mediated non-scarring alopecia often associated with substantial morbidity. There are however, limited population-based data on potential disparities in the burden of AA, including across people of different ethnicities and deprivation. We aimed to provide the first large-scale, population-based estimate of lifetime risk of AA overall and by important sociodemographic subgroups. As AA is associated with an increased burden of mental health conditions and work-related outcomes (unemployment, time off work), a detailed understanding of the burden of disease in different sociodemographic groups is vital to plan resource provision.
Detailed description
The overall purpose of the study is to provide an estimate of the cumulative lifetime incidence of AA in the population overall and by important sociodemographic groups. Moreover, to do a subgroup analysis in the AA population to identify health-related disparities across people in different socioeconomic strata, geographical distribution, sex and ethnic groups. The disparities that will be considered are AA associated: Mental health conditions; healthcare utilisation; and work impact (time off work and unemployment). The cumulative lifetime risk of AA was estimated at age 80 years (approximate life expectancy in the UK) using survival models, with age as the timescale and accounting for the competing risk of death. The assessment of any associations with baseline characteristics and the outcomes of interest will be assessed using Cox proportional hazards models (time to event outcomes) and Poisson regression (repeated event outcomes) models.
Interventions
OTHERNo intervention
Observational analysis of usual care only.
Sponsors
Pfizer
University of Oxford
Momentum Data
Study design
Observational model
COHORT
Time perspective
RETROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
12 Years to 95 Years
Inclusion criteria
* Patients aged greater than 12 over the study period. * Registered with the contributing primary care practice for any duration during the study period
Exclusion criteria
* People diagnosed with AA before the study period.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Likelihood of Depressive Episodes | Data was collected retrospectively, assessed prior to and up to two years following initial Alopecia Areata diagnosis for each participant | Estimated using logistic regression and reported using adjusted odds ratios |
| Likelihood of Recurrent Major Depressive Disorder | Data was collected retrospectively, assessed prior to and up to two years following initial Alopecia Areata diagnosis for each participant | Estimated using logistic regression and reported using adjusted odds ratios |
| Likelihood of Anxiety Disorder | Data was collected retrospectively, assessed prior to and up to two years following initial Alopecia Areata diagnosis for each participant | Estimated using logistic regression and reported using adjusted odds ratios |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Relative Incidence of Unemployment | Data was collected retrospectively, assessed up to two years following initial Alopecia Areata diagnosis for each participant | Unemployment identified by issue of IB113 or ESA113 forms for unemployment. Relative incidence estimated using Cox proportional hazard regression and reported as Adjusted hazard ratio |
| Relative Incidence of Primary Care Attendances | Data was collected retrospectively, assessed up to two years following initial Alopecia Areata diagnosis for each participant | Estimated using negative binomial regression and reported as adjusted incidence rate ratio |
| Relative Incidence of Time Off Work | Data was collected retrospectively, assessed up to two years following initial Alopecia Areata diagnosis for each participant | Time off work identified by recorded issue of Med 3 certificate in primary care. Relative incidence estimated using Cox proportional hazard regression and reported as Adjusted hazard ratio |
| Relative Incidence of Dermatology Referrals | Data was collected retrospectively, assessed up to two years following initial Alopecia Areata diagnosis for each participant | Estimated using Cox proportional hazard regression and reported as Adjusted hazard ratio |
| Relative Incidence Psychological Therapy | Data was collected retrospectively, assessed up to two years following initial Alopecia Areata diagnosis for each participant | Estimated using Cox proportional hazard regression and reported as adjusted hazard ratio |
Countries
United Kingdom
Participant flow
Recruitment details
Of the 4,052,231 adults and children (aged 12+) in the final study population, 6,183 people who developed Alopecia Areata (AA) between 1 January 2009 and 31 December 2018 were matched to 24,718 people without AA.
Pre-assignment details
People that did not develop Alopecia Areata but had a diagnosis of a nonspecific or alopecia alternative condition, or less than 12 months of follow-up available, were excluded from the study.
Participants by arm
| Arm | Count |
|---|---|
| People With Alopecia Areata Children and adults aged 12+ with new onset Alopecia Areata registered with a contributing General practitioner (GP) practice during the study period.
No intervention: Observational analysis of usual care only. | 6,183 |
| People Without Alopecia Areata Children and adults aged 12+ without Alopecia Areata registered with a contributing GP practice during the study period.
No intervention: Observational analysis of usual care only. | 24,718 |
| Total | 30,901 |
Baseline characteristics
| Characteristic | People With Alopecia Areata | People Without Alopecia Areata | Total |
|---|---|---|---|
| Age, Continuous | 35 years | 35 years | 35 years |
| Age, Customized 12-17 | 529 Participants | 2111 Participants | 2640 Participants |
| Age, Customized 18-29 | 1699 Participants | 6792 Participants | 8491 Participants |
| Age, Customized 30-49 | 2666 Participants | 10659 Participants | 13325 Participants |
| Age, Customized 50+ | 1289 Participants | 5156 Participants | 6445 Participants |
| Alcohol status Alcoholism | 117 Participants | 314 Participants | 431 Participants |
| Alcohol status Hazardous use | 686 Participants | 2596 Participants | 3282 Participants |
| Alcohol status Non-drinker | 1272 Participants | 4628 Participants | 5900 Participants |
| Alcohol status Not recorded | 1358 Participants | 6253 Participants | 7611 Participants |
| Alcohol status Safe use | 2750 Participants | 10927 Participants | 13677 Participants |
| Body Mass Index (BMI), Categorical 18.5-25 Normal weight | 2277 Participants | 8842 Participants | 11119 Participants |
| Body Mass Index (BMI), Categorical < 18.5 Underweight | 315 Participants | 1303 Participants | 1618 Participants |
| Body Mass Index (BMI), Categorical 25-30 Overweight | 1644 Participants | 5901 Participants | 7545 Participants |
| Body Mass Index (BMI), Categorical 30-35 Class I obesity | 665 Participants | 2664 Participants | 3329 Participants |
| Body Mass Index (BMI), Categorical 35-40 Class II obesity | 245 Participants | 941 Participants | 1186 Participants |
| Body Mass Index (BMI), Categorical 40+ Class III obesity | 132 Participants | 496 Participants | 628 Participants |
| Body Mass Index (BMI), Categorical Not recorded | 905 Participants | 4571 Participants | 5476 Participants |
| Geographical region East Midlands | 227 Participants | 904 Participants | 1131 Participants |
| Geographical region East of England | 253 Participants | 1009 Participants | 1262 Participants |
| Geographical region London | 1488 Participants | 5952 Participants | 7440 Participants |
| Geographical region North East | 209 Participants | 833 Participants | 1042 Participants |
| Geographical region North West | 1160 Participants | 4640 Participants | 5800 Participants |
| Geographical region Not recorded | 127 Participants | 507 Participants | 634 Participants |
| Geographical region South East | 1053 Participants | 4212 Participants | 5265 Participants |
| Geographical region South West | 635 Participants | 2540 Participants | 3175 Participants |
| Geographical region West Midlands | 417 Participants | 1665 Participants | 2082 Participants |
| Geographical region Yorkshire and The Humber | 614 Participants | 2456 Participants | 3070 Participants |
| Geographic area: Urban, Rural Not recorded | 120 Participants | 480 Participants | 600 Participants |
| Geographic area: Urban, Rural Rural | 913 Participants | 3648 Participants | 4561 Participants |
| Geographic area: Urban, Rural Urban | 5150 Participants | 20590 Participants | 25740 Participants |
| Index of multiple deprivation (IMD) 1 (most deprived) | 1339 Participants | 5356 Participants | 6695 Participants |
| Index of multiple deprivation (IMD) 2 | 1277 Participants | 5108 Participants | 6385 Participants |
| Index of multiple deprivation (IMD) 3 | 1091 Participants | 4356 Participants | 5447 Participants |
| Index of multiple deprivation (IMD) 4 | 1144 Participants | 4573 Participants | 5717 Participants |
| Index of multiple deprivation (IMD) 5 (least deprived) | 1205 Participants | 4818 Participants | 6023 Participants |
| Index of multiple deprivation (IMD) Not recorded | 127 Participants | 507 Participants | 634 Participants |
| Race/Ethnicity, Customized Asian | 1129 Participants | 4515 Participants | 5644 Participants |
| Race/Ethnicity, Customized Black | 241 Participants | 960 Participants | 1201 Participants |
| Race/Ethnicity, Customized Not recorded | 1344 Participants | 5376 Participants | 6720 Participants |
| Race/Ethnicity, Customized Other | 264 Participants | 1047 Participants | 1311 Participants |
| Race/Ethnicity, Customized White | 3205 Participants | 12820 Participants | 16025 Participants |
| Sex: Female, Male Female | 3342 Participants | 13366 Participants | 16708 Participants |
| Sex: Female, Male Male | 2841 Participants | 11352 Participants | 14193 Participants |
| Smoking status Active smoker | 1868 Participants | 5561 Participants | 7429 Participants |
| Smoking status Ex-smoker | 1529 Participants | 5741 Participants | 7270 Participants |
| Smoking status Non-smoker | 2538 Participants | 11676 Participants | 14214 Participants |
| Smoking status Not recorded | 248 Participants | 1740 Participants | 1988 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 0 | 0 / 0 |
| other Total, other adverse events | 0 / 0 | 0 / 0 |
| serious Total, serious adverse events | 0 / 0 | 0 / 0 |
Outcome results
Primary
Likelihood of Anxiety Disorder
Estimated using logistic regression and reported using adjusted odds ratios
Time frame: Data was collected retrospectively, assessed prior to and up to two years following initial Alopecia Areata diagnosis for each participant
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| People With Alopecia Areata | Likelihood of Anxiety Disorder | 1113 Participants |
| People Without Alopecia Areata (Reference Group) | Likelihood of Anxiety Disorder | 3188 Participants |
95% CI: [1.3, 1.51]
Primary
Likelihood of Depressive Episodes
Estimated using logistic regression and reported using adjusted odds ratios
Time frame: Data was collected retrospectively, assessed prior to and up to two years following initial Alopecia Areata diagnosis for each participant
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| People With Alopecia Areata | Likelihood of Depressive Episodes | 1217 Participants |
| People Without Alopecia Areata (Reference Group) | Likelihood of Depressive Episodes | 3576 Participants |
95% CI: [1.25, 1.46]
Primary
Likelihood of Recurrent Major Depressive Disorder
Estimated using logistic regression and reported using adjusted odds ratios
Time frame: Data was collected retrospectively, assessed prior to and up to two years following initial Alopecia Areata diagnosis for each participant
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| People With Alopecia Areata | Likelihood of Recurrent Major Depressive Disorder | 835 Participants |
| People Without Alopecia Areata (Reference Group) | Likelihood of Recurrent Major Depressive Disorder | 2264 Participants |
95% CI: [1.32, 1.58]
Secondary
Relative Incidence of Dermatology Referrals
Estimated using Cox proportional hazard regression and reported as Adjusted hazard ratio
Time frame: Data was collected retrospectively, assessed up to two years following initial Alopecia Areata diagnosis for each participant
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| People With Alopecia Areata | Relative Incidence of Dermatology Referrals | 1352 Count of dermatology referrals |
| People Without Alopecia Areata (Reference Group) | Relative Incidence of Dermatology Referrals | 743 Count of dermatology referrals |
95% CI: [7.55, 9.04]
Secondary
Relative Incidence of Primary Care Attendances
Estimated using negative binomial regression and reported as adjusted incidence rate ratio
Time frame: Data was collected retrospectively, assessed up to two years following initial Alopecia Areata diagnosis for each participant
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| People With Alopecia Areata | Relative Incidence of Primary Care Attendances | 39034 Count of primary care visits |
| People Without Alopecia Areata (Reference Group) | Relative Incidence of Primary Care Attendances | 109052 Count of primary care visits |
95% CI: [1.37, 1.46]
Secondary
Relative Incidence of Time Off Work
Time off work identified by recorded issue of Med 3 certificate in primary care. Relative incidence estimated using Cox proportional hazard regression and reported as Adjusted hazard ratio
Time frame: Data was collected retrospectively, assessed up to two years following initial Alopecia Areata diagnosis for each participant
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| People With Alopecia Areata | Relative Incidence of Time Off Work | 884 Count of Med 3 certificates issued |
| People Without Alopecia Areata (Reference Group) | Relative Incidence of Time Off Work | 2268 Count of Med 3 certificates issued |
95% CI: [1.38, 1.61]
Secondary
Relative Incidence of Unemployment
Unemployment identified by issue of IB113 or ESA113 forms for unemployment. Relative incidence estimated using Cox proportional hazard regression and reported as Adjusted hazard ratio
Time frame: Data was collected retrospectively, assessed up to two years following initial Alopecia Areata diagnosis for each participant
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| People With Alopecia Areata | Relative Incidence of Unemployment | 89 Count of unemployment forms issued |
| People Without Alopecia Areata (Reference Group) | Relative Incidence of Unemployment | 209 Count of unemployment forms issued |
95% CI: [1.14, 1.87]
Secondary
Relative Incidence Psychological Therapy
Estimated using Cox proportional hazard regression and reported as adjusted hazard ratio
Time frame: Data was collected retrospectively, assessed up to two years following initial Alopecia Areata diagnosis for each participant
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| People With Alopecia Areata | Relative Incidence Psychological Therapy | 248 Count of therapy visits |
| People Without Alopecia Areata (Reference Group) | Relative Incidence Psychological Therapy | 672 Count of therapy visits |
95% CI: [1.17, 1.57]