What is the male to female ratio in Primary Sclerosing Cholangitis (PSC) associated with Inflammatory Bowel Disease (IBD)?

Male to Female Ratio in Primary Sclerosing Cholangitis (PSC) Associated with Inflammatory Bowel Disease (IBD)

The male to female ratio in Primary Sclerosing Cholangitis (PSC) associated with Inflammatory Bowel Disease (IBD) is approximately 2:1. 1

Epidemiology of PSC-IBD

PSC is a chronic, cholestatic liver disease characterized by an inflammatory and fibrotic process affecting both intra- and extrahepatic bile ducts. This condition has several important epidemiological features:

• Male predominance with a male to female ratio of 2:1 1
• Mean age of diagnosis around 40 years 1
• PSC can be diagnosed in children and elderly, but is most common in young to middle-aged adults 1
• Up to 80% of PSC patients have concomitant IBD 1
• In most cases, IBD is diagnosed as ulcerative colitis (UC) rather than Crohn's disease 1

IBD Association with PSC

The relationship between PSC and IBD has several notable characteristics:

• IBD is present in 62-83% of patients with PSC of Northern European descent 1
• IBD prevalence in PSC patients can be as low as 21% in other parts of the world 1
• When PSC is associated with UC, there is a clear male predominance with a male/female ratio ranging from 65/35 to 70/30 2
• PSC is more common in UC than in Crohn's disease 2
• Prevalence of PSC ranges from 0.76% to 5.4% in UC patients 2
• Prevalence of PSC ranges from 1.2% to 3.4% in Crohn's disease patients 2

Regional Variations

Studies from different regions confirm the male predominance but show some variations:

• In a Swiss IBD Cohort Study, PSC was significantly more prevalent in UC compared to Crohn's disease (4.04% vs. 0.58%) 3
• A Taiwanese study found a 1.57% prevalence of PSC in IBD patients, with all cases occurring in UC patients, and male sex was identified as a risk factor for PSC in pediatric patients with IBD 4

Risk Factors for PSC in IBD Patients

Several risk factors have been identified for PSC in patients with ulcerative colitis:

• Male sex (odds ratio 2.771) 3
• Pancolitis (odds ratio 2.855) 3
• Nonsmoker status at diagnosis (odds ratio 9.253) 3
• History of appendicectomy (odds ratio 4.114) 3

Clinical Implications

The 2:1 male to female ratio in PSC-IBD has important clinical implications:

• The "typical" PSC patient is a young to middle-aged man with IBD who presents with biochemical and/or clinical signs of cholestatic liver disease 1
• Male patients with IBD, particularly UC, should be monitored more closely for signs of PSC
• Routine evaluation of biliary enzymes and liver imaging is recommended in young male patients with IBD 4
• PSC-IBD patients have worse survival compared to IBD patients without PSC 3
• UC-PSC patients develop colorectal cancer more frequently compared to UC patients without PSC 3

Conclusion

Understanding the male predominance in PSC-IBD is important for clinical practice, as it helps identify patients at higher risk who may benefit from closer monitoring and earlier intervention. The consistent finding of a 2:1 male to female ratio across multiple studies and guidelines provides strong evidence for this epidemiological pattern.