Table 5.
Pre-planned subgroup analyses based on country of research origin, age group, and alopecia severity.
| Alopecia areata | Androgenetic alopecia | Telogen effluvium | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Subgroup | No. of studies | Prevalence | I2 (%)/p-value of Q test | No. of studies | Prevalence | I2 (%)/p-value of Q test | No. of studies | Prevalence | I2 (%)/p-value of Q test |
| Overall | 34 | 51.94% (41.54–62.25%) | 97.48/<0.01 | 16 | 47.27% (32.49–62.29%) | 96.06/<0.01 | 13 | 53.51% (37.33–69.33%) | 97.99/<0.01 |
| Country | |||||||||
| Eastern | 28 | 56.70% (43.04–69.87%) | 97.88/<0.01 | 9 | 64.31% (48.41–78.81%) | 92.10/<0.01 | 9 | 64.42% (49.17–78.33%) | 97.10/<0.01 |
| Western | 6 | 31.36% (23.51–39.74%) | 82.73/<0.01 | 7 | 25.54% (16.80–35.34%) | 82.88/<0.01 | 4 | 27.56% (13.59–44.07%) | 88.11/<0.01 |
| Age | |||||||||
| Mean age 18–25 years | 3 | 47.01% (1.32–96.78%) | – | 3 | 70.69% (51.32–86.96%) | – | 0 | – | – |
| Mean age 25–60 years | 29 | 54.67% (44.56–64.60%) | 96.79/<0.01 | 11 | 42.07% (25.49–59.60%) | 96.42/<0.01 | 9 | 56.00% (38.63–72.67%) | 97.70/<0.01 |
| Mean age > 60 years | 1 | 5.56% (0.99–25.76%) | – | 1 | 14.81% (5.92–32.48%) | – | 1 | 28.57% (19.32–40.05%) | – |
| Unspecified | 1 | 35.00% (18.12–56.71%) | – | 1 | 68.00% (54.19–79.24%) | – | 1 | 10.43% (6.07–17.36%) | – |
| Severity | |||||||||
| Severe cohorts | 9 | 44.36% (19.70–70.54%) | 98.01/<0.01 | – | – | – | – | – | – |
| Non-severe cohorts | 13 | 63.71% (47.43–78.58%) | 95.25/<0.01 | ||||||
| Unspecified | 12 | 44.64% (31.88–57.75%) | 96.90/<0.01 | ||||||
| Subgroup | No. of studies | Odds ratio | I2 (%)/p-value of Q test | No. of studies | Odds ratio | I2 (%)/p-value of Q test | No. of studies | Odds ratio | I2 (%)/p-value of Q test |
|---|---|---|---|---|---|---|---|---|---|
| Overall | 24 | 2.84 (1.89–4.26) | 84.29/<0.01 | 7 | 3.43 (0.95–12.35) | 95.16/<0.01 | 5 | 1.14 (0.65–1.98) | 48.09/0.10 |
| Country | |||||||||
| Eastern | 20 | 3.18 (2.04–4.97) | 75.74/<0.01 | 5 | 5.65 (1.75–18.18) | 79.96/<0.01 | 4 | 1.04 (0.56–1.94) | 53.62/0.09 |
| Western | 4 | 1.78 (0.77–4.16) | 91.62/<0.01 | 2 | 1.00 (0.18–5.59) | 91.52/<0.01 | 1 | 1.97 (0.60–6.46) | – |
| Age | |||||||||
| Mean age 18–25 years | 2 | 6.65 (1.22–36.35) | 90.06/<0.01 | 1 | 13.50 (4.22–43.21) | – | 0 | – | – |
| Mean age 25–60 years | 22 | 2.57 (1.70–3.88) | 82.36/<0.01 | 6 | 2.73 (0.74–10.15) | 93.99/<0.01 | 5 | 1.14 (0.65–1.98) | 48.09/0.10 |
| Severity | |||||||||
| Severe cohorts | 8 | 3.29 (1.30–8.34) | 85.53/<0.01 | – | – | – | – | – | – |
| Non-severe cohorts | 11 | 3.58 (2.20–5.82) | 60.92/<0.01 | ||||||
| Unspecified | 5 | 1.62 (0.71–3.71) | 91.62/<0.01 | ||||||
| Subgroup | No. of studies | Mean difference | I2 (%)/p-value of Q test | No. of studies | Mean difference | I2 (%)/p-value of Q test | No. of studies | Mean difference | I2 (%)/p-value of Q test |
|---|---|---|---|---|---|---|---|---|---|
| Overall | 33 | −8.20 (−10.28 – −6.12) | 74.25/<0.01 | 15 | −6.39 (−9.81 – −2.97) | 88.56/<0.01 | 8 | −5.71 (−10.10 – −1.32) | 92.46/<0.01 |
| Country | |||||||||
| Eastern | 30 | −8.24 (−10.02 – −6.46) | 58.11/<0.01 | 12 | −8.13 (−11.97 – −4.29) | 87.64/<0.01 | 7 | −6.07 (−11.02 – −1.13) | 93.47/<0.01 |
| Western | 3 | −6.67 (−23.12–9.77) | 85.29/<0.01 | 3 | −0.52 (−8.58–7.54) | 84.55/<0.01 | 1 | −4.10 (−8.36–0.16) | – |
| Age | |||||||||
| Mean age 18–25 years | 5 | −8.98 (−12.23 – −5.73) | 0.00/1.00 | 1 | −9.24 (−11.28 – −7.20) | – | 0 | – | – |
| Mean age 25–60 years | 27 | −8.07 (−10.44 – −5.70) | 78.12/<0.01 | 12 | −5.81 (−9.49 – −2.13) | 90.34/<0.01 | 7 | −6.74 (−11.69 – −1.80) | 93.44/<0.01 |
| Mean age > 60 years | 0 | – | – | 0 | – | – | 0 | – | – |
| Unspecified | 1 | −12.43 (−18.47 – −6.39) | – | 2 | −10.37 (−18.94 – −1.80) | 88.56%/0.65 | 1 | 0.43 (−3.77–4.63) | – |
| Severity | |||||||||
| Severe cohorts | 8 | −10.65 (−15.23 – −6.07) | 44.83/0.08 | – | – | – | – | – | – |
| Non-severe cohorts | 17 | −8.17 (−9.97 – −6.37) | 15.12/0.28 | ||||||
| Unspecified | 8 | −5.92 (−10.36 – −1.47) | 89.79/<0.01 | ||||||