Four causes account for the excess mortality in Sjögren disease

Design

Population-based data linkage cohort study with 1:5 matched controls and competing-risk analysis, 1980-2013

Population

457 primary Sjögren disease, 218 with rheumatoid arthritis, 77 with other connective tissue disease, and 3,716 matched controls in Western Australia

Primary outcome

All-cause and cause-specific mortality compared with matched controls

Effect

Primary Sjögren HR 1.8 (95% CI 1.5-2.0); with rheumatoid arthritis 2.1 (1.8-2.5); with other connective tissue disease 3.1 (2.2-4.3); 25-year survival in primary disease 77%

Western Australian registry data linked from 1980 to 2013 identified 457 patients with primary Sjögren disease, 218 with Sjögren disease alongside rheumatoid arthritis and 77 alongside another connective tissue disease, each matched 1:5 to controls - 3,716 controls in all, with 1,345 deaths among them.

Mortality was higher in every Sjögren group. Primary disease carried a hazard ratio of 1.8 (95% CI 1.5-2.0), Sjögren with rheumatoid arthritis 2.1 (1.8-2.5), and Sjögren with another connective tissue disease 3.1 (2.2-4.3). Survival in primary disease at the end of 25 years of follow-up was 77% (95% CI 0.63-0.94). Competing-risk and multiple-cause-of-death analysis identified where the excess sits: infection, ischaemic heart disease, lymphoid malignancy and interstitial lung disease.

That list is the reason to read this. Sjögren disease is still routinely managed as a symptom problem - dryness, fatigue, the things the patient raises - and the four causes of excess death are each things a review appointment could address and usually does not. Vaccination status and infection risk, cardiovascular risk factors, the lymphoma red flags, and whether anyone has listened to the lungs or measured the lung function. None of that is exotic; it is the difference between managing the complaint and managing the disease.

• Check vaccination status at review; infection was one of the four excess causes of death
• Assess and treat cardiovascular risk factors as you would in rheumatoid arthritis
• Ask about persistent parotid swelling and check complement and paraprotein status - lymphoid malignancy is the classic Sjögren risk
• Ask about breathlessness and cough, and have a threshold for lung function testing
• Record whether the Sjögren disease is primary or associated; the associated forms carried markedly higher risk

Why it matters

The things these patients die of are not the things their appointments are spent on.

Don't overread it

Administrative data to 2013, identified by diagnostic code - the absolute risk for a patient diagnosed now is likely lower.

The statistics, in plain English

The confidence interval on the 77% survival figure - 0.63 to 0.94 - is wide, which reflects how few patients remain at 25 years rather than uncertainty about the direction. The hazard ratios are more precisely estimated and consistent across all three groups, which is the more persuasive pattern. Two cautions about the cohort: identification was by ICD code, which will capture the patients sick enough to be coded and miss milder disease, and follow-up ran to 2013, before current treatment and before the current understanding of cardiovascular risk in connective tissue disease. Both would tend to overstate the mortality gap for a patient diagnosed today.

Read the rest in the app

You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.

Get Daily Doctor — free

Scan to keep reading on your phone. No account needed to start.