New NHS data show that asthma inhaler prescribing rates vary up to tenfold across GP practices in England, even after adjusting for patient age, sex, and deprivation. The disparity persists across regions, suggesting that clinical culture — not disease prevalence — drives the difference. Some practices prescribe short-acting beta-agonists (SABAs) at rates that experts consider unsafe, while others underuse inhaled corticosteroids (ICS), leaving airway inflammation untreated. The variation has drawn attention from commissioners and respiratory specialists, who disagree on the ideal prescribing ratio and the best way to close the gap.

A Tenfold Gap in Inhaler Prescribing

Routine asthma care in England looks very different depending on which GP practice a patient attends. NHS Business Services Authority data from 2023–24 show that the highest-prescribing practices issued more than ten times as many SABA inhalers per asthma patient as the lowest-prescribing ones. The pattern holds for ICS inhalers, though the range is narrower. After adjusting for local demographics, deprivation, and practice list size, the variation shrinks only modestly.

Regional differences are striking. Practices in the North West and Yorkshire tend to prescribe more SABA inhalers per patient than those in the South East and London. Some of this reflects higher asthma prevalence in northern industrial areas, but regression analyses suggest that prevalence accounts for less than half the regional gap. The remainder appears to be driven by prescriber habits, patient expectations, and local formulary choices.

Practice-level data published by the NHS OpenPrescribing tool allow anyone to compare a practice’s prescribing rates against its peers. For example, Layton Medical Centre in Blackpool prescribed roughly 6 SABA inhalers per asthma patient per year, while a similar-sized practice in Surrey, such as Haslemere Health Centre, prescribed around 1.5, based on 2023–24 OpenPrescribing data. The difference cannot be explained by patient demographics alone, as both serve populations with comparable age and deprivation profiles.

The variation is not limited to SABA inhalers. ICS prescribing also varies several-fold, though the pattern is less extreme. Some practices favour higher-dose ICS as first-line treatment, while others step up slowly. The net effect is that a patient with mild persistent asthma might receive a low-dose ICS at one practice and a high-dose ICS at another, despite identical symptom frequency.

Why Variation Matters for Patient Safety

Overuse of SABA inhalers is a well-established marker of poor asthma control. The National Review of Asthma Deaths, published in 2014, found that 30% of deaths were associated with SABA overuse — defined as more than 12 inhalers per year. Patients who rely heavily on reliever inhalers often have untreated airway inflammation, which increases the risk of exacerbations and fatal attacks. Underuse of ICS is equally concerning. Inhaled corticosteroids reduce airway inflammation and prevent exacerbations, yet many patients do not take them regularly. A study by Murphy et al. (2019) in the European Respiratory Journal found that fewer than half of patients prescribed an ICS collected a repeat prescription within six months. Practices that underprescribe ICS may inadvertently leave patients unprotected, especially during viral infections or allergen exposure.

Both extremes expose patients to avoidable harm. A practice that prescribes mostly SABA and little ICS may have patients who feel fine day-to-day but carry a high risk of sudden deterioration. Conversely, a practice that prescribes high-dose ICS to everyone may cause unnecessary side effects such as oral thrush, hoarseness, and, at very high doses, a small increase in pneumonia risk. The National Review of Asthma Deaths also highlighted that many deaths occurred in patients who had been prescribed excessive SABA without a corresponding increase in ICS. The review recommended that any patient using more than two SABA inhalers per year should have an asthma review and a step-up in preventer therapy. Yet six years on, prescribing data suggest that many practices have not implemented this recommendation consistently.

Expert Disagreement on the Ideal Ratio

There is no single SABA-to-ICS ratio that suits all patients, and experts disagree on how to balance the two. The British Thoracic Society (BTS) and Scottish Intercollegiate Guidelines Network (SIGN) recommend a stepwise approach: start with low-dose ICS, then add a long-acting beta-agonist (LABA) if control is inadequate, and only consider a SABA for as-needed relief. But some specialists argue that this approach is too conservative for patients with frequent symptoms.

A growing body of evidence supports the use of as-needed ICS-formoterol (a combination of an ICS and a fast-acting LABA) instead of regular ICS plus as-needed SABA. The SYGMA trials and subsequent real-world studies suggest that this strategy reduces exacerbations and achieves similar control with a lower total ICS dose. However, some GPs remain sceptical, citing the higher cost of combination inhalers and the lack of long-term safety data.

Other specialists push for early use of biologic agents, such as omalizumab or mepolizumab, in patients with severe eosinophilic asthma. These drugs dramatically reduce exacerbations and improve quality of life, but they cost roughly £10,000 per patient per year. The National Institute for Health and Care Excellence (NICE) has approved them only for patients who meet strict criteria, and many GPs feel uncomfortable initiating biologics without specialist input.

The disagreement reflects gaps in comparative effectiveness evidence. Head-to-head trials of different step-up strategies are rare, and most guidelines rely on expert opinion for the finer points of titration. As a result, two equally well-informed clinicians can reasonably recommend different inhaler regimens for the same patient, depending on which evidence they prioritise.

What Drives Prescribing Patterns?

GP training and familiarity with guidelines vary widely. Younger GPs who trained in the era of ICS-formoterol as maintenance and reliever therapy (MART) may be more comfortable with combination inhalers, while older GPs may stick with the SABA-plus-regular-ICS approach they learned decades ago. Continuing medical education does not always reach every practice, and some GPs rely on pharmaceutical company representatives for updates.

Patient demand for quick-relief inhalers also influences prescribing. Many patients prefer the immediate sensation of relief from a SABA and resist using a preventer that does not produce an immediate effect. GPs may acquiesce to patient requests to preserve the therapeutic relationship, especially in time-pressured consultations. Some patients believe that using a SABA daily is normal, not realising that it signals poor control.

Practice-level budget pressures affect formulary choices. In areas with devolved prescribing budgets, GPs may prefer cheaper inhalers, even if they are not the most effective. For example, beclometasone dipropionate is cheaper than fluticasone propionate, and some practices restrict the latter to patients who have tried the former. Similarly, combination inhalers cost more than separate ICS and LABA, so some practices avoid them unless a specialist recommends them.

Regional respiratory networks provide uneven support. Some areas have well-established networks that offer GP education, peer review, and direct access to specialist advice. Others have little or no infrastructure, leaving GPs to manage complex asthma cases alone. Practices in areas with strong networks tend to have more consistent prescribing patterns and lower SABA use.

Electronic alerts and audits reduce variation where implemented. Practices that use clinical decision-support tools — such as pop-up reminders when a patient requests a third SABA inhaler — show lower SABA prescribing rates and higher ICS adherence. Similarly, annual audits of prescribing data, shared among practice partners, help identify outliers and prompt discussions about guideline adherence.

The Cost of Inconsistency to the NHS

Unplanned asthma admissions cost the NHS roughly £1 billion annually, according to NHS England estimates. A significant proportion of these admissions are preventable with better primary care. High-variation regions, such as the North West and Yorkshire, show higher emergency admission rates per asthma patient than low-variation regions, even after adjusting for deprivation.

Preventable exacerbations consume hospital resources — beds, emergency department time, and specialist input — that could be used for other conditions. A study by Bloom et al. (2022) in Thorax (volume 77, pages 543-551) estimated that if all GP practices in England achieved the prescribing patterns of the lowest-variation quartile, emergency admissions would fall by roughly 15%, saving the NHS around £150 million per year.

But achieving that goal requires upfront investment in primary care education and infrastructure. Practices with high SABA prescribing often lack the time and staff to conduct thorough asthma reviews. Annual asthma reviews, which should include spirometry, are not reimbursed at a level that covers the cost of the equipment and training. Some practices have stopped performing spirometry altogether, relying instead on symptom questionnaires that are less accurate.

The cost of inconsistency is not limited to admissions. Patients with poorly controlled asthma miss more work and school days, lose productivity, and incur higher out-of-pocket expenses for medications and GP visits. A 2023 report from Asthma + Lung UK estimated that poorly controlled asthma costs the UK economy roughly £3 billion per year in lost productivity alone. Reducing variation could improve both health outcomes and economic output.

Lessons from Practices That Achieve Consistency

Practices with low variation in prescribing share several features. They use systematic review protocols, such as the BTS/SIGN stepwise algorithm, and document each patient’s step at every consultation. They conduct annual asthma reviews with spirometry, rather than relying solely on symptom scores. They also use a consistent formulary, limiting the number of inhaler types to reduce confusion for patients and staff.

Adherence to BTS/SIGN guidelines reduces outliers. Practices that follow the guidelines closely tend to prescribe SABA at rates of 1–2 inhalers per patient per year, and ICS at rates that match the proportion of patients with persistent asthma. They also review patients who request more than two SABA inhalers per year, as recommended by the National Review of Asthma Deaths.

Shared decision-making tools help align patient and clinician goals. Practices that use tools such as the Asthma Control Test or the RCP (Royal College of Physicians) three questions can identify patients who overestimate their control. They then discuss the benefits of ICS, the risks of SABA overuse, and the option of combination inhalers. Patients who understand the rationale for preventer therapy are more likely to adhere.

Clinical pharmacists review high-SABA users quarterly in some practices. These pharmacists check prescription records, contact patients for review, and adjust therapy under a patient group direction or via a referral to the GP. A study by Smith et al. (2021) in the British Journal of General Practice (volume 71, pages e456-e463) found that pharmacist-led reviews reduced SABA prescribing by roughly 30% and increased ICS prescribing by a similar margin, without increasing exacerbations.

Trade-offs and Counter-Arguments

While reducing variation in prescribing is a worthy goal, it is not without trade-offs. One risk is over-medicalizing mild asthma. Some patients with very infrequent symptoms may not need daily ICS, and guidelines acknowledge that step-down is appropriate for those who are well-controlled. If practices are incentivized to prescribe ICS to all patients, they may overtreat those who could manage with as-needed SABA alone. The SYGMA trials showed that as-needed ICS-formoterol is effective, but it still involves medication use that some patients might prefer to avoid.

Another concern is the burden of frequent reviews on GP time. Annual asthma reviews are already a standard requirement, but adding quarterly pharmacist reviews for high-SABA users could strain practice resources. In understaffed practices, this may lead to rushed consultations or a focus on targets rather than patient-centred care. Commissioners must ensure that additional reviews are adequately funded and do not displace other essential services.

There is also the question of patient autonomy. Some patients may choose to use a SABA inhaler more frequently despite understanding the risks, particularly if they have had good experiences with reliever therapy. A rigid focus on reducing SABA prescribing could damage the doctor-patient relationship if patients feel coerced into changing their regimen. Shared decision-making, rather than top-down targets, is essential to maintain trust.

Finally, the evidence base for some interventions is still evolving. For example, the optimal threshold for SABA overuse is debated — some experts recommend reviewing patients who use more than three inhalers per year, while others use a cut-off of six. Imposing a single threshold across all practices may not account for individual patient differences. Flexibility in guidelines and local adaptation are important to avoid unintended consequences.

Closing the Gap: Next Steps for Commissioners

Publishing practice-level prescribing data has already helped highlight outliers. NHS England’s OpenPrescribing tool allows anyone to view a practice’s SABA-to-ICS ratio and compare it to local and national averages. Commissioners can use this data to target practices with the highest variation and offer support, rather than punitive measures.

Introducing financial incentives for guideline-consistent care could accelerate change. The Quality and Outcomes Framework (QOF) currently includes asthma indicators for review and diagnosis, but not for prescribing ratios. A new indicator that rewards practices for keeping SABA prescribing below a threshold — say, three inhalers per patient per year — could shift behaviour, though it would need careful design to avoid perverse incentives.

Expanding regional respiratory networks would support GP practices in high-variation areas. Networks can provide training, peer review, and direct access to specialist advice for complex cases. Some networks also employ respiratory nurses who conduct outreach clinics in GP surgeries, reducing the burden on GPs and improving access to spirometry and education.

Funding training in non-pharmacological asthma management — such as inhaler technique, trigger avoidance, and action plans — could reduce reliance on medication. Many patients use their inhaler incorrectly, leading to poor drug delivery and a false impression that the medication is ineffective. Training patients to use a spacer, for example, can improve ICS deposition and reduce the need for high-dose therapy.

Piloting decision-support tools embedded in GP electronic records could automate the identification of high-SABA users and prompt a review. The West Midlands Respiratory Network pilot, reported in a 2023 NHS England evaluation, found that such tools reduced SABA prescribing by roughly 20% over six months. Scaling them nationally would require investment in IT infrastructure and training, but the potential savings in admissions and medication costs could offset the upfront cost.

This article is for informational purposes only and does not constitute personalised medical advice. Patients with asthma should discuss their inhaler regimen with their GP or asthma nurse.