What is the Gera Chronic Disease Burden Index?

The Gera Chronic Disease Burden Index (GCDBI) is a Gera Systems 0–100 measure of an ICB's overall recorded chronic-disease burden. For each ICB it sums the ratio of the area's real QOF prevalence to the England rate across diabetes, hypertension, coronary heart disease, dementia, asthma and depression, then maps the median ICB to 50. It uses only real NHS England QOF 2024/25 figures.

Why normalise each condition to the England rate?

Hypertension affects around 15% of patients while dementia affects under 1%. Without normalising, hypertension would dominate the index. Dividing each ICB prevalence by the England rate puts every condition on a comparable scale (England = 1.0), so the index reflects relative burden across all six conditions rather than just the most common one.

Is the index reproducible?

Yes. Every input is the real, published NHS England QOF 2024/25 prevalence data under the Open Government Licence v3.0. The four steps above are the complete calculation — anyone can download the same file and reproduce every index value. Gera invents no numbers.

Which ICB currently has the highest chronic-disease burden?

On the QOF 2024/25 data, NHS Lincolnshire Integrated Care Board has the highest Gera Chronic Disease Burden Index (78.5/100), with diabetes prevalence 8.8% and hypertension 19.0%. See the cluster hub for the full ranking.

Does a high index mean an area has worse healthcare?

No. The index measures recorded chronic-disease prevalence, which is driven mainly by age structure, deprivation and ethnicity, plus how completely practices code diagnoses. Older, more deprived areas tend to score higher. It is not a measure of care quality and not a prediction of any individual’s risk.

Gera Chronic Disease Burden Index — Methodology

The complete, reproducible formula behind the Gera Chronic Disease Burden Index, computed only from real NHS England QOF 2024/25 prevalence data across all 42 English ICBs.

The formula

raw(ICB) = Σ over 6 conditions of ( ICB_prevalence ÷ England_prevalence )

GCDBI = 50 + ( raw − median_raw ) ÷ half_span × 50 (clamped 0–100)

where an ICB at the England rate for all six conditions scores raw = 6.0, the median ICB maps to 50, and half_span is the larger of (max − median) and (median − min) across all 42 ICBs. A hypothetical England-average ICB equates to 45.3.

Step by step

Take the real source figures. For every GP practice in England, read the QOF register count and the matching denominator list size for each of the six conditions from NHS England's 2024/25 QOF raw data (PREVALENCE_2425.csv). No estimates are introduced.
Aggregate to ICB prevalence. Map each practice to its parent Integrated Care Board, then compute each ICB's recorded prevalence per condition as 100 × sum(register) ÷ sum(list size). This reproduces NHS England's published England headline rates exactly.
Normalise each condition to England. For each ICB and condition, divide the ICB prevalence by the England prevalence. An ICB exactly at the England rate scores 1.0 for that condition, so every condition contributes comparably regardless of how common it is overall.
Sum and index 0–100. Sum the six ratios to a raw burden (an England-average ICB scores 6.0). Map the median ICB raw burden to 50, and the ICB furthest from the median to the 0 or 100 bound, linearly and clamped. Higher = greater population-weighted chronic-disease burden.

Highest chronic-disease burden (2024/25)

Top 5 English ICBs by Gera Chronic Disease Burden Index
Integrated Care Board	Diabetes	Hypertension	Gera Chronic Disease Burden Index
Lincolnshire	8.8%	19.0%	78.5 / 100
Cornwall and the Isles of Scilly	7.6%	18.1%	76.9 / 100
Somerset	8.2%	18.7%	74.7 / 100
Norfolk and Waveney	9.0%	18.1%	74.6 / 100
North East and North Cumbria	8.9%	17.9%	71.9 / 100

The six conditions covered are diabetes, hypertension, coronary heart disease, dementia, asthma, depression.

Why this index, and what it is not

A single condition cannot summarise an area's chronic-disease burden, and the most common condition would otherwise dominate any naive sum. The Gera Chronic Disease Burden Index normalises each condition to the England rate so all six contribute comparably, then indexes ICBs around the median. It reflects recorded prevalence — driven by age, deprivation, ethnicity and diagnosis coding — not the quality of local care, and never a prediction for any individual.

Gera Chronic Disease Burden Index: frequently asked questions

What is the Gera Chronic Disease Burden Index?: The Gera Chronic Disease Burden Index (GCDBI) is a Gera Systems 0–100 measure of an ICB's overall recorded chronic-disease burden. For each ICB it sums the ratio of the area's real QOF prevalence to the England rate across diabetes, hypertension, coronary heart disease, dementia, asthma and depression, then maps the median ICB to 50. It uses only real NHS England QOF 2024/25 figures.
Why normalise each condition to the England rate?: Hypertension affects around 15% of patients while dementia affects under 1%. Without normalising, hypertension would dominate the index. Dividing each ICB prevalence by the England rate puts every condition on a comparable scale (England = 1.0), so the index reflects relative burden across all six conditions rather than just the most common one.
Is the index reproducible?: Yes. Every input is the real, published NHS England QOF 2024/25 prevalence data under the Open Government Licence v3.0. The four steps above are the complete calculation — anyone can download the same file and reproduce every index value. Gera invents no numbers.
Which ICB currently has the highest chronic-disease burden?: On the QOF 2024/25 data, NHS Lincolnshire Integrated Care Board has the highest Gera Chronic Disease Burden Index (78.5/100), with diabetes prevalence 8.8% and hypertension 19.0%. See the cluster hub for the full ranking.
Does a high index mean an area has worse healthcare?: No. The index measures recorded chronic-disease prevalence, which is driven mainly by age structure, deprivation and ethnicity, plus how completely practices code diagnoses. Older, more deprived areas tend to score higher. It is not a measure of care quality and not a prediction of any individual’s risk.

Explore the data

Contains public sector information published by NHS England and licensed under the Open Government Licence v3.0. Source: NHS England (NHS Digital) — Quality and Outcomes Framework (QOF) prevalence (2024/25, published 28 August 2025).