Statistics sheet — asthma
Last curated: 2026-10-29 (new rows marked 2026-10-29; older rows retain their verification dates). Journal sources were resolved through live PubMed E-utilities in their originating audit or dated sweep. Values preserve the study population, comparator and uncertainty; they should not be mixed across settings without recalibration. The WHO fact sheet (363 million / 442,000 deaths, 28 April 2026) was re-opened 2026-10-29 and is unchanged.
1. Global burden
| Figure |
Population / method |
Source |
| 260 million prevalent asthma cases (95% uncertainty interval 227–298 million) in 2021 |
GBD 2021, 204 countries/territories |
GBD 2021 Asthma and Allergic Diseases Collaborators 2025, PMID 40147466 |
| 436,000 asthma deaths in 2021 |
GBD 2021 modeled estimate; the point estimate was retained, but an uncertainty interval not reproduced in the live record was removed during audit |
PMID 40147466 |
| Age-standardized prevalence fell 40.0% from 5,568.3 to 3,340.1 per 100,000, 1990–2021 |
GBD 2021 |
PMID 40147466 |
| 275 million projected cases (95% UI 224–330 million) in 2050 |
GBD forecast; population growth dominant |
PMID 40147466 |
| Modifiable factors accounted for 29.9% of asthma DALYs |
High BMI, occupational asthmagens, smoking and NO2 modeled |
PMID 40147466 |
| South Asia age-standardized asthma DALY rate 465.0 per 100,000 (95% UI 357.2–648.9) |
Highest GBD super-region estimate in 2021 |
PMID 40147466 |
| 363 million people affected and 442,000 deaths in 2023 2026-10-15 |
WHO fact sheet citing IHME 2025; a later GBD round than the 2021 figures above, which is not directly comparable with them. Shown side by side, not reconciled |
(World Health Organization — "Asthma" fact sheet, 28 April 2026, https://www.who.int/news-room/fact-sheets/detail/asthma, accessed 2026-10-15) |
| US$863 billion (95% UI 615–1,396; 2024 US$) asthma-attributable macroeconomic loss, 2025–2050; annual GDP decline 0.036% (0.026–0.058) 2026-10-15 |
Health-augmented macroeconomic model, 154 countries; USA US$471 billion, UK US$45 billion, China US$44 billion; high-income countries US$712 billion, low-income US$5 billion. Abstract-level |
Cao 2026, PMID 42520825 |
| Self-reported asthma 8.1% (ages 6–7) and 4.8% (ages 13–14); objective testing supported 41.6% and 61.0% of these; <5% used ICS 2026-10-15 |
CHEST-Africa school survey, n=4,477, four African countries; spirometry and FeNO after self-report. Abstract-level |
Ozoh 2026, PMID 42744587 |
US surveillance checked 2026-10-22
| Figure |
Population / method |
Source |
| Current asthma: 27,807,000 people, 8.4% (SE 0.18); children <18: 6.7%; adults ≥18: 8.9% 2026-10-22 |
US NHIS 2023, weighted survey; ever diagnosed and still has asthma. CDC page dated 6 October 2026; observation year remains 2023 |
(CDC — “Most Recent Asthma Data”, accessed 2026-10-22) |
| Current asthma: adults ≥18, 8.5%; children <18, 6.3% 2026-10-22 |
US NHIS 2025, as reported in the live FastStats page; a different observation year from the table above |
(CDC/NCHS — “Asthma” FastStats, accessed 2026-10-22) |
| 3,722 deaths; 1.1 per 100,000 2026-10-22 |
US NVSS 2024 mortality, as reported in FastStats; distinct from NHIS prevalence |
(CDC/NCHS — “Asthma” FastStats, accessed 2026-10-22) |
2. Diagnostic accuracy and instability
FeNO diagnosis
| Metric |
Estimate |
Source |
| Sensitivity |
0.65 (95% CI 0.58–0.72) |
26 studies, 4,518 participants; Karrasch 2017, PMID 27388487 |
| Specificity |
0.82 (0.76–0.86) |
Same meta-analysis |
| Diagnostic odds ratio |
9.23 (6.55–13.01) |
Same meta-analysis |
| AUC |
0.80 (0.77–0.85) |
Same meta-analysis |
| Specificity increase per 10-ppb higher threshold |
OR 1.46 |
Same meta-regression |
| Adult FeNO AUC vs bronchial provocation, normal spirometry 2026-10-15 |
0.80 (0.73–0.85); children 0.75 (0.65–0.82) |
22 adult studies (n=7,141), 9 paediatric (n=989); Roy 2026, PMID 42743935. Abstract-level |
| Adult FeNO ≥65 ppb PPV / <20 ppb NPV at 20% prevalence 2026-10-15 |
80% (72–86) / 93% (91–94), 18% (12–25) missed |
Same; rule-out threshold derived post hoc |
| Adult blood eosinophil AUC 2026-10-15 |
0.65 (0.59–0.71); no added value to FeNO |
Same |
| Estimated community prevalence of BEC ≥0.3×10⁹/L among Australian adults with asthma 2026-10-29 |
24.3% (95% CI 14.4–34.3) |
Imputation from NOVELTY (n=818) onto a nationally representative web survey (n=1,510); Poulos 2026, PMID 42950894. Abstract-level |
| Estimated community prevalence of FeNO ≥25 ppb among Australian adults with asthma 2026-10-29 |
42.6% (31.9–53.3) |
Same; asthma+COPD and COPD-only estimates are lower. Not a diagnostic threshold study |
| Figure |
Population / method |
Source |
| Current asthma ruled out in 203/613, 33.1% (95% CI 29.4–36.8) |
Canadian multicenter taper, spirometry and serial challenge |
Aaron 2017, PMID 28114551 |
| No evidence remained at 12 months in 181/613, 29.5% (25.9–33.1) |
Prospective follow-up |
PMID 28114551 |
| Serious cardiorespiratory alternative diagnosis in 12/613, 2.0% |
Same cohort |
PMID 28114551 |
| Objective airflow testing at original diagnosis: 43.8% when later ruled out vs 55.6% when confirmed |
Absolute difference 11.8% (2.1–21.5) |
PMID 28114551 |
3. Mild asthma and reliever trials
START
| Outcome |
Budesonide |
Placebo |
Effect |
| Participants with severe event |
117/3,597 |
198/3,568 |
HR 0.56 (95% CI 0.45–0.71) |
| Post-BD FEV1 advantage |
— |
— |
+1.48 percentage points year 1; +0.88 year 3 |
| Growth under age 11 |
— |
— |
−1.34 cm over 3 years |
Source: Pauwels 2003, PMID 12672309.
SYGMA 1
| Outcome |
Terbutaline PRN |
Budesonide–formoterol PRN |
Maintenance budesonide |
| Well-controlled weeks |
31.1% |
34.4% |
44.4% |
| Severe attacks/year |
0.20 |
0.07 |
0.09 |
| PRN budesonide–formoterol effect |
Reference |
RR 0.36 (0.27–0.49) |
vs maintenance RR 0.83 (0.59–1.16) |
| Median metered ICS/day |
0 |
57 μg |
340 μg |
Source: O'Byrne 2018, PMID 29768149.
SYGMA 2 and pragmatic trials
| Trial / outcome |
Estimate |
Source |
| SYGMA 2 severe attacks/year |
0.11 PRN ICS–formoterol vs 0.12 maintenance budesonide; RR 0.97, upper one-sided 95% limit 1.16 |
Bateman 2018, PMID 29768147 |
| SYGMA 2 median metered ICS |
66 vs 267 μg/day |
PMID 29768147 |
| Novel START exacerbations/year |
0.195 PRN budesonide–formoterol vs 0.400 albuterol; RR 0.49 (0.33–0.72) |
Beasley 2019, PMID 31112386 |
| CARE children attacks/year |
0.23 PRN budesonide–formoterol vs 0.41 salbutamol; RR 0.55 (0.35–0.86) |
Hatter 2025, PMID 41033330 |
| Pooled ICS–formoterol vs SABA severe attacks |
RR 0.65 (0.60–0.72); risk difference −10.3% (−11.8 to −8.3) |
Rayner 2025, PMID 39465893 |
| Pooled ICS–SABA vs SABA severe attacks |
RR 0.84 (0.73–0.95); risk difference −4.7% (−8.0 to −1.5) |
PMID 39465893 |
4. Severe asthma biologics
| Trial |
Population |
Primary attack result |
Other anchor |
| DREAM mepolizumab |
621 recurrent-attack eosinophilic severe asthma |
2.40/year placebo vs 1.24, 1.46, 1.15 across doses; reductions 48%, 39%, 52% |
No clear dose gradient |
| SIROCCO benralizumab |
Severe eosinophilic asthma |
Significant attack reduction in eosinophil-enriched population |
Lung-function response varied by regimen |
| LIBERTY QUEST dupilumab |
1,902 uncontrolled moderate-to-severe asthma |
Severe exacerbation RR 0.52 (95% CI 0.41–0.66) for 200-mg regimen vs placebo |
FEV1 +0.14 L vs placebo |
| NAVIGATOR tezepelumab |
1,061 severe uncontrolled asthma |
0.93 vs 2.10/year; RR 0.44 (0.37–0.53) |
FEV1 difference +0.13 L (0.08–0.18) |
| NAVIGATOR eosinophils <300 |
Prespecified subgroup |
1.02 vs 1.73/year; RR 0.59 (0.46–0.75) |
Broad but not biomarker-independent benefit |
5. Triple therapy
| Figure |
Evidence |
Source |
| Severe exacerbation: 22.7% triple vs 27.4% dual |
RR 0.83 (95% CI 0.77–0.90) |
20 RCTs, 11,894 participants; Kim 2021, PMID 34009257 |
| Symptom/QOL changes |
Average differences did not reach minimal important differences |
Same meta-analysis |
6. Preschool and childhood asthma
| Figure |
Population |
Source |
| Daily medium-dose ICS vs placebo severe attacks |
RR 0.70 (95% CI 0.61–0.79), NNT 9 |
22 trials, 4,550 preschool children; Kaiser 2016, PMID 27230765 |
| Persistent-asthma subgroup |
RR 0.56 (0.46–0.70), NNT 11 |
Same meta-analysis |
| Daily ICS vs montelukast |
RR 0.59 (0.38–0.92) |
One trial within same review |
| MIST daily vs intermittent budesonide |
0.97 (0.76–1.22) vs 0.95 (0.75–1.20) OCS-requiring attacks/year |
278 high-risk preschoolers; Zeiger 2011, PMID 22111718 |
| CAMP hospitalization |
2.5 vs 4.4 per 100 person-years, budesonide vs placebo |
1,041 children, 4–6 years; PMID 11027739 |
| CAMP urgent visits |
12 vs 22 per 100 person-years |
PMID 11027739 |
| CAMP height gain |
1.1 cm less with budesonide |
PMID 11027739 |
| ICS >12 months, first-year growth velocity |
−0.48 cm/year (95% CI −0.66 to −0.29) |
16 RCTs; Loke 2015, PMID 26191797 |
| Adult height, budesonide trial |
−1.20 cm (−1.90 to −0.50) |
Same systematic review |
| CAMP early-adult clinical remission |
26.0% |
879 participants; Wang 2019, PMID 30445065 |
| CAMP strict remission |
15.0% |
741 with airway-responsiveness data; PMID 30445065 |
DIVA adjunctive vitamin D trial 2026-10-22
| Outcome |
Population / method |
Source |
| Rescue OCS courses/child over 7 months: 0.67 vitamin D3 versus 0.71 placebo; IRR 0.95 (95% CI 0.70–1.30) |
Canadian children aged 1–5 with high-morbidity, viral-induced asthma; 160 versus 163 randomized, against planned total 865. Imprecise result; not evidence about preventing asthma onset |
Ducharme 2026, PMID 42871976; full text, Table 2 |
7. Inhaler technique and adherence
| Figure |
Evidence |
Source |
| Overall device errors |
50–100% across included studies |
Chrystyn 2017, PMID 28373682 |
| Critical device errors |
14–92%; heterogeneity generally >90% |
PMID 28373682 |
| Education and critical errors |
RR 0.28 (95% CI 0.17–0.47) |
Marko 2025, PMID 40102397 |
| Education and any dry-powder error |
RR 0.38 (0.21–0.70) |
PMID 40102397 |
| Education and any MDI error |
RR 0.16 (0.11–0.23) |
PMID 40102397 |
| Mean ICS adherence |
22–63% across studies |
Bårnes 2015, PMID 25118311 |
| Pediatric adherence intervention |
Hedges g 0.39 (0.24–0.54) post-intervention; follow-up g 0.38 (−0.08 to 0.83) |
Fidler 2021, PMID 34343294 |
| Pharmacist-led adherence intervention |
SMD 0.49 (0.35–0.64) |
Mes 2018, PMID 29976652 |
| Electronic-monitor adherence |
Random-effects SMD 0.41 (0.22–0.60) |
Garin 2023, PMID 36986513 |
8. Supported self-management
| Outcome |
Effect |
Source |
| Hospitalization |
RR 0.64 (95% CI 0.50–0.82) |
36 trials; Gibson 2003, PMID 12535399 |
| Emergency visits |
RR 0.82 (0.73–0.94) |
Same review |
| Unscheduled clinician visits |
RR 0.68 (0.56–0.81) |
Same review |
| Work/school absence |
RR 0.79 (0.67–0.93) |
Same review |
| Nocturnal asthma |
RR 0.67 (0.56–0.79) |
Same review |
| Quality of life |
SMD 0.29 (0.11–0.47) |
Same review |
| School program ED visits |
OR 0.70 (0.53–0.92) |
Kneale 2019, PMID 30686788 |
| School program hospitalization |
SMD −0.19 (−0.35 to −0.04) |
Same review |
9. Biomarkers
| Marker strategy |
Effect |
Source |
| Sputum-guided therapy, ≥1 attack |
62 vs 82 per 100; OR 0.36 (0.21–0.62) |
Petsky 2018, PMID 29858277 |
| Adult FeNO-guided, ≥1 attack |
OR 0.61 (0.44–0.83) |
12 RCTs, 2,116 adults; Korevaar 2023, PMID 37293870 |
| Adult FeNO-guided attack rate |
RR 0.67 (0.54–0.82) |
Same review |
| Pediatric FeNO-guided, children with attacks |
RR 0.73 (0.63–0.84) |
23 RCTs; Wang 2020, PMID 32525611 |
| Pediatric FeNO-guided ICS dose |
+64.17 μg/day (53.59–74.75) |
Same review |
| Serum periostin diagnosis |
Sensitivity 0.68 (0.42–0.86), specificity 0.87 (0.76–0.93) |
Jia 2021, PMID 31738608 |
10. Comorbidity and mimics
| Figure |
Population / caveat |
Source |
| Laryngeal dysfunction prevalence |
25% (95% CI 15–37), I²=96%; selected asthma cohorts with objective laryngoscopy |
Lee 2020, PMID 31940470 |
| Bronchiectasis prevalence |
36.6% (307/839); selected CT-imaged cohorts |
Zhang 2021, PMID 33530179 |
| Bronchiectasis FEV1/FVC difference |
−2.71 percentage points (−3.72 to −1.69) |
Same meta-analysis |
| Bronchiectasis attack difference |
+0.68/year (0.03–1.33) |
Same meta-analysis |
| OSA prevalence in adult asthma |
49.5% (36.4–62.6) |
Kong 2017, PMID 28642543 |
| Asthma–OSA association |
OR 2.64 (1.76–3.52) |
Same meta-analysis |
| GERD–asthma exacerbation association |
OR 1.27 (1.18–1.35) |
32 studies, 1.61 million; Mallah 2022, PMID 34448255 |
| Allergic-rhinitis association with asthma |
OR 4.24 (3.82–4.71) |
Rogliani 2023, PMID 36889783 |
11. Pregnancy
| Outcome in maternal asthma |
Relative risk (95% CI) |
Source |
| Low birthweight |
1.46 (1.22–1.75) |
Murphy 2011, PMID 21749633 |
| Small for gestational age |
1.22 (1.14–1.31) |
Same meta-analysis |
| Preterm delivery |
1.41 (1.22–1.61) |
Same meta-analysis |
| Pre-eclampsia |
1.54 (1.32–1.81) |
Same meta-analysis |
| Preterm delivery under active management |
1.07 (0.91–1.26) |
Subgroup, same meta-analysis |
| Exacerbation risk: obesity |
RR 1.25 (1.15–1.37) |
Robijn 2022, PMID 35705210 |
| Exacerbation risk: smoking |
RR 1.35 (1.04–1.75) |
Same review |
| Exacerbation risk: depression/anxiety |
RR 1.42 (1.27–1.59) |
Same review |
| Exacerbation risk: moderate–severe vs mild |
RR 3.44 (2.03–5.83) |
Same review |
12. SABA and systemic steroid safety
| Figure |
Evidence |
Source |
| SABA overuse prevalence |
30% collected ≥3 canisters in baseline year |
Swedish cohort n=365,324; Nwaru 2020, PMID 31949111 |
| Attack risk, 3–5 canisters |
HR 1.26 (1.24–1.28) |
Same cohort |
| Attack risk, 6–10 canisters |
HR 1.44 (1.41–1.46) |
Same cohort |
| SABA ≥3 canisters and mortality |
RR 2.04 (1.37–3.04) |
27-study meta-analysis; Tsao 2025, PMID 40491263 |
| Systemic steroid and osteoporosis/fracture |
adjusted HR 3.11 (1.87–5.19) |
Matched cohort; Price 2018, PMID 30214247 |
| Systemic steroid and pneumonia |
HR 2.68 (2.30–3.11) |
Same cohort |
| OCS and osteoporosis |
pooled HR 1.76 (1.48–2.09) |
Chalitsios 2021, PMID 33799052 |
| Severe-asthma registry ≥500 mg OCS/year |
44% |
Politis 2024, PMID 38622806 |
| Severe-asthma registry ≥1,000 mg OCS/year |
32% |
Same registry |
| Cumulative systemic GCS at which most adverse effects rise significantly 2026-10-15 |
500 mg–1 g prednisolone-equivalent, dose-dependent |
EAACI task-force meta-analysis, upper and lower airway disease; Scheire 2026, PMID 42011838. Abstract-level |
13. Inequity and patient priorities
| Figure |
Evidence |
Source |
| Lowest vs highest income attack odds |
OR 1.25 (1.13–1.37) |
Gassasse 2025, PMID 40688041 |
| Same, children |
OR 1.36 (1.23–1.50) |
Same meta-analysis |
| Same, adults |
OR 1.19 (1.05–1.33) |
Same meta-analysis |
| Lower SES and ED attendance |
OR 1.61 (1.40–1.84) |
Redmond 2022, PMID 34673047 |
| Lower SES and hospitalization |
OR 1.63 (1.34–1.99) |
Same review |
| Patient goals aligning with clinician goals |
53% |
Severe-asthma cohorts; Mulvey 2021, PMID 33577946 |
| Severe Asthma Questionnaire test–retest ICC |
0.93 |
Hyland 2018, PMID 29794132 |
Known conflicts and interpretation caveats
- GBD uncertainty intervals are modeled uncertainty, not sampling confidence intervals.
- Trial relative effects require the comparator’s baseline event rate for individual absolute benefit.
- Observational SABA/OCS associations include confounding by disease severity, but dose-response supports safety action.
- Diagnostic sensitivity/specificity changes with threshold, spectrum, treatment and reference standard.
- Biomarker thresholds are drug-, assay-, age- and population-specific.
- Prevalence estimates from specialty or imaged cohorts should not be applied to community asthma.
- “Remission” definitions differ and must specify on-treatment versus off-treatment state.
- Global prevalence: the WHO fact sheet's 363 million (2023, citing IHME 2025) and GBD 2021's 260 million differ by roughly 40%. The sweep did not retrieve the IHME release behind the WHO figure, so the gap is not explained here. Cite each with its year and source, and do not trend between them.
- CHEST-Africa shows that symptom-questionnaire prevalence can overstate confirmed asthma (only 41.6–61.0% objectively supported) while understating diagnosis and treatment.