Two in five patients with IPF have hypertension, and one in four has reflux

Design

Systematic review and meta-analysis of observational studies with narrative synthesis of outcome associations

Population

251 studies, 606,398 adults with idiopathic pulmonary fibrosis, each study with at least 100 patients

Primary outcome

Pooled prevalence of comorbidities and their association with health outcomes

Effect

Hypertension 39% (95% CI 34–44); dyslipidaemia 30% (20–38); gastro-oesophageal reflux 27% (23–31); diabetes 21% (19–23); heart failure 15% (13–18). Lung cancer alone consistently associated with higher mortality

This review pooled 251 observational studies of at least 100 adults each, covering 606,398 patients with idiopathic pulmonary fibrosis, to establish what else these patients have. Systemic hypertension came out at 39% (95% CI 34–44), dyslipidaemia 30% (20–38), gastro-oesophageal reflux disease 27% (23–31), hiatus hernia 20% (9–33), overweight or obesity 22% (18–27), diabetes 21% (19–23), ischaemic heart disease 20% (17–23) and heart failure 15% (13–18).

The comparison the authors draw is the important one: these rates are generally higher than in the clinical trial cohorts that generate the treatment evidence. The patient in front of you carries more comorbidity than the patient the antifibrotic was tested on, which affects tolerability, drug interactions and what an exacerbation will do.

On outcomes the review is appropriately cautious. Few studies examined how comorbidities relate to quality of life or disease progression, and the associations that exist were synthesised narratively rather than pooled. Only lung cancer was consistently associated with higher short-term and long-term mortality — which is both the least surprising finding and the one with the clearest implication for surveillance.

• Take a cardiovascular history at IPF diagnosis; one in five has ischaemic heart disease and one in seven has heart failure.
• Ask about reflux symptoms explicitly — over a quarter have gastro-oesophageal reflux disease and it is frequently unreported.
• Keep lung cancer in mind throughout follow-up; it is the comorbidity most clearly linked to mortality here.
• Check for drug interactions between antifibrotics and the cardiovascular and metabolic drugs most of these patients are already taking.
• Remember that trial tolerability data come from a less comorbid population than the one in your clinic.

Why it matters

Antifibrotic tolerability and exacerbation risk were established in patients less sick than the ones being treated.

Don't overread it

These are prevalence estimates from observational cohorts; apart from lung cancer, no comorbidity was shown to affect IPF outcomes.

The statistics, in plain English

Pooled prevalence estimates from 251 observational studies carry wide variation in how comorbidity was ascertained — some from coded records, some from clinical assessment — which is why the interval for hiatus hernia runs from 9% to 33%. Narrower intervals, such as diabetes at 19–23%, reflect more consistent ascertainment rather than a more reliable disease association. The mortality finding for lung cancer is narrative rather than pooled, so it describes consistency of direction across studies, not a quantified risk.

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