Population range revision · 8 September 2026
One range.
Every assumption visible.
Compare Callegari’s 1.0 million US CLTI benchmark, an illustrative 1.5 million midpoint and Barnes’s 2.0 million benchmark through the same assessment pathway.
Move the controls to explore the arithmetic. The activation and infection-return rates are assumptions here; they must be measured before making a patient forecast.
Compare the assessment scenarios
| Assessment pathway | Callegari 2024 1.0M benchmark | 1.5M midpoint Illustrative only | Barnes 2020 2.0M benchmark |
|---|---|---|---|
| Disease pool | 1,000,000 | 1,500,000 | 2,000,000 |
| Entering active assessment | 1,000,000 | 1,500,000 | 2,000,000 |
| After provisional infection step | 900,000 | 1,350,000 | 1,800,000 |
| Meeting all treatment criteria | Must be measured | Must be measured | Must be measured |
Remaining for assessment does not establish eligibility. Assess wound, perfusion, infection status, salvageability and all applicable treatment criteria. No automatic diagnosis-code percentage is deducted.
Two published CLTI estimates
Cited in the epidemiologic introduction of a prognostic study after peripheral vascular intervention. This is background synthesis, not a new national prevalence survey.
Read the manuscript ↗Barnes et al. · ATVB 2020~2 millionUS adults over 40 with CLTIThe review reports 1.28% prevalence in adults over 40, approximately 2 million people, citing Duff et al. 2019.
Read the manuscript ↗The range is not a confidence interval, pooled estimate or new national survey. The 1.5M midpoint is arithmetic only. Harmonize source year, age, coding and definition to IQVIA’s age-50-and-older population.
The third manuscript · broader PAD context
Deng et al. 2025
16.41 million people with PAD in high-income North America in 2021 (95% uncertainty interval 14.68–18.34 million), projected to 31.08 million in 2050. These are GBD-based regional PAD estimates.
This is not a third US CLTI estimate. The regional total is not the US total. The “up to 11%” PAD-to-CLTI statement in the CLTI literature cannot be applied to it to establish national CLTI prevalence or an annual transition rate.
Read Deng et al. · Research 2025 · Table 1 ↗Keep the full range in the model
| Assessment pathway | Callegari 2024 1.0M benchmark | 1.5M midpoint Illustrative only | Barnes 2020 2.0M benchmark |
|---|---|---|---|
| US CLTI disease pool | 1,000,000 | 1,500,000 | 2,000,000 |
| Entering active assessment | 1,000,000 × A | 1,500,000 × A | 2,000,000 × A |
| After provisional infection step | 900,000 × A | 1,350,000 × A | 1,800,000 × A |
| Meeting all treatment criteria | Must be measured | Must be measured | Must be measured |
A is the share entering assessment with active disease in the stated period and must be measured. The provisional infection scenario retains 90%: 60% initially without infection + 40% initially infected × 75% returning. These are people remaining for further assessment, not established treatment candidates.
For example, if A = 50%, 500,000 / 750,000 / 1,000,000 people enter assessment and 450,000 / 675,000 / 900,000 remain after the provisional infection step. The 50% is an arithmetic example, not an estimated rate.
Vary return after infection across every benchmark
Hold the assumed infection prevalence at 40% and vary how many initially infected people return to assessment. All counts below also depend on the measured activation fraction A.
| Initially infected patients returning | Whole-cohort non-return | 1.0M Callegari | 1.5M midpoint | 2.0M Barnes |
|---|---|---|---|---|
| 0% | 40% | 600,000 × A | 900,000 × A | 1,200,000 × A |
| 50% | 20% | 800,000 × A | 1,200,000 × A | 1,600,000 × A |
| 62.5% | 15% | 850,000 × A | 1,275,000 × A | 1,700,000 × A |
| 75% | 10% | 900,000 × A | 1,350,000 × A | 1,800,000 × A |
| 87.5% | 5% | 950,000 × A | 1,425,000 × A | 1,900,000 × A |
These are assumption-based counts remaining for assessment. Death, limb loss, clinical improvement and other exits need a consistent time window and must not be counted twice. Recurrent qualifying episodes can bring a previously diagnosed person back into care.
Explain the commercial assumptions in plain language.
| Existing IQVIA assumption | What it means |
|---|---|
| About 28.6% prescribing share | Clinicians would prescribe to about 29 of every 100 patients remaining after the model’s clinical filters. |
| 60% of stated prescribing intent | Keep 60% of that initial prescribing estimate, reducing it by another 40%. |
| About 65.8% access | About 66 of every 100 patients remaining at this step obtain treatment. |
These are commercial forecast assumptions. They do not establish clinical need or who can benefit. We have removed the previous 82,404–92,171 treatment estimates because they depended on an unsupported clinical exclusion. A validated treated-patient forecast still requires measured clinical eligibility. The separate asterisked discussion waterfall retains a 9.4% deduction only as an unvalidated scenario assumption, with all dependent numbers marked accordingly.
Follow the same person through chronic disease.
Infections are often transient and treatable. Underlying ischemic disease and wound risk can persist, progress and recur. Individual episodes can improve and wounds can heal into remission; those people still need follow-up.
Connect existing disease, first diagnoses, untreated carryover and recurrent episodes to each year’s clinical population. Count people separately from ulcers, limbs and repeat treatments. The supplied IQVIA model’s 290,836 first diagnoses and 15,977 treated patients are different measures; neither independently establishes the full eligible population.