Nearly half the Hajj heat-illness patients in a 2024 review were 60 or older

A cross-sectional study covering nine healthcare facilities in Makkah and the Mashaer region during the 2024 Hajj identified 1,576 patients meeting diagnostic criteria for heat exhaustion or heatstroke, of whom 77 died — an overall mortality rate of 4.9% [s1].

The paper, published on 11 April, is one of the few systematic clinical characterisations of heat-related illness at a mass gathering, and it arrives in a research literature that a separate scoping review describes as strikingly sparse for the region as a whole [s2].

What the caseload looked like

Investigators retrospectively extracted records using a standardised form from healthcare facility registries, screening 2,785 patients, of whom 2,551 had complete clinical records and 1,576 met the diagnostic criteria with outcome data available [s1].

The demographic profile is the part most relevant to prevention. Most patients were male — 1,171, or 74.3% [s1]. Nearly half were 60 or older: 776 patients, 49.2%, with a further 693 (44.0%) aged 39 to 59 [s1]. The overwhelming majority, 1,419 or 90%, were non-Saudi pilgrims, primarily from Arab countries, with 793 (50.3%) from those countries [s1].

And 1,094 patients — 69.4% — had no prior history of heat-related illness [s1]. That figure undercuts one of the more intuitive triage heuristics. If roughly seven in ten cases occur in people with no previous episode, prior history is a poor filter for identifying who needs protecting.

Presentation and treatment

Altered mental status was the most common presenting symptom, in 635 patients (40.3%), followed by dizziness in 486 (30.8%) [s1]. Management included intravenous fluid administration in 569 cases (36.1%) and application of cooling measures in emergency settings for 1,105 patients (70.1%) [s1].

Altered mental status leading the symptom list matters in a specific operational way: it is the presentation that makes a patient least able to seek help. In a very large crowd, a person who has become confused is dependent on someone else noticing.

The study found that intensive care unit admission and elevated lactic acid levels were significantly associated with poor outcomes [s1]. Both are markers of severity rather than independent causes, so this is best read as confirmation that the severity gradient behaves as expected rather than as a novel prognostic finding.

The design limits

This is a retrospective chart review across nine facilities, not a cohort followed prospectively, and it counts people who presented for care. It cannot describe pilgrims who became unwell and did not reach a facility, nor those who reached one of the many facilities not included among the nine. The denominator problem is real: without a total pilgrim count linked to the same catchment, "prevalence" here describes the composition of a clinical caseload rather than a population risk.

The authors' conclusions are correspondingly practical — early recognition, timely intervention, targeted education for high-risk groups, and strengthened frontline preparedness [s1] — rather than epidemiological estimates of risk.

The research vacuum the second paper documents

A scoping review published in GeoHealth in June 2025 searched three databases for studies published between 2010 and 2024 assessing the relationship between extreme heat and health outcomes anywhere in the Arabian Peninsula. It found twelve [s2].

Twelve studies, across fifteen years, for a region where wet-bulb temperature is projected to surpass theoretical human tolerance limits during the twenty-first century [s2].

The distribution is as uneven as the total is small: eight of the twelve were conducted in Kuwait, four in Saudi Arabia, and one each in Qatar, Oman, Yemen and the United Arab Emirates [s2]. Most used average temperature as the exposure (nine studies), assessed daily (ten), from one or several meteorological stations (nine) in a single city (eight) [s2]. Outcomes were predominantly daily-level (ten) mortality (nine) assessed at an ecological rather than individual scale (ten) [s2].

Why the methodological detail matters

Single-city, single-station, ecological mortality studies are the cheapest design available and the least able to answer the questions that would drive policy. They cannot say who within a population is vulnerable, cannot separate outdoor from indoor exposure, and cannot evaluate whether a specific intervention worked.

The review notes that while most studies included confounders (ten), the selection was not always consistent with best practices; most did not assess effect modification (eight), and none investigated modification by land-cover and land-use change [s2]. That last omission is pointed. Urban form — how much of a city is asphalt versus vegetation, where shade exists, how heat is retained overnight — is one of the few levers a government can actually pull, and no study in the review examined it.

What to watch next

Whether the Hajj clinical data gets linked to exposure measurement. The 2024 study characterises who arrived at a hospital and what happened to them; it does not connect that to measured temperature, humidity, or crowd density at the time and place of exposure. Combining a well-documented clinical caseload with the meteorological and geospatial data the GeoHealth review found missing is the step that would turn a description of casualties into an evaluation of what protects people.

Sources

1. Prevalence and Risk Factors of Heat-Related Illness Among Pilgrims During the Hajj Season 2024: A Cross-Sectional Study — Journal of Epidemiology and Global Health, 11 April 2026 (primary)
2. Overheated and Understudied: A Scoping Review of Heat-Related Health Impacts in the Arabian Peninsula — GeoHealth, 30 June 2025 (primary)