Acute hepatic porphyria prevalence more common in women

Acute hepatic porphyria (AHP) is more commonly seen in women in Denmark, with acute intermittent porphyria (AIP) the the most frequent subtype.

That’s according to a recent study that also found that patients with high levels of porphobilinogen, a porphyrin precursor that builds up to toxic levels in AHP patients, in the urine were more likely to develop AHP symptoms, but not to be hospitalized or require treatment.

“This study provides information on the Danish population of patients with AHP. Such information is important to understand the disease manifestation of the AHP population and to recognize AHP patients in a clinical setting,” the researchers wrote. The study, “Acute hepatic porphyria in Denmark; a retrospective study,” was published in the Orphanet Journal of Rare Diseases.

Porphyria is caused by genetic mutations that disrupt the production of heme, a molecule essential for oxygen transport, leading to the toxic accumulation of intermediate molecules called porphyrins and their precursors. AHP includes several porphyria types that are marked by the accumulation of porphyrin precursors in the liver, particularly porphobilinogen (PBG) and aminolevulinic acid (ALA). Symptoms include pain, gastrointestinal problems, and neurological issues, that usually manifest during acute attacks.

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Studying prevalence of AHP, symptoms

To learn more about the characteristics of people with AHP in Denmark, researchers conducted a five-year retrospective study using the electronic journals of AHP patients who’d been followed at the department of endocrinology at Odense University Hospital between 2017 and 2022.

The study included 129 patients (65.9% women) with newly diagnosed or established AHP who were a mean age of 46.3. Most (77.5%) had AIP, the most common type of AHP, while 13.2% had variegate porphyria, and 9.3% had hereditary coproporphyria.

Twenty patients were hospitalized at least once due to AHP symptoms and 11 were hospitalized for acute attacks that required treatment with human hemin (sold as Normosang) for at least four days. Three patients receiving preventive treatment with hemin for chronic symptoms were also hospitalized. All the hospitalized patients also received glucose, a sugar molecule that inhibits porphyrin precursor production.

The most common factors that led to acute attacks included stress, infections, alcohol, medications, fasting, and menstrual/hormonal changes. During attacks, most patients had abdominal pain (94.7%), followed by neurological issues (31.6%), nausea and vomiting (28.9%).

Outside of attacks, urinary PBG levels were moderately elevated in 24% of the patients and high in 30.2%, while urinary ALA levels were normal in most patients (64.3%). During the five-year follow-up, 38 patients (29.5%) reported having AHP-related symptoms at least once, most being women (68.4%).

AHP symptoms were more common with high urinary PBG levels than with moderate or normal PBG levels (53.8% vs. 25.8% vs. 17.5%). Patients with high urinary PBG levels were 2.5 times more likely to have symptoms than those with normal or moderate PBG levels.

The researchers didn’t see a relationship between urinary PBG levels and the number of hospitalizations or treatments, however. They estimated the prevalence of AHP in Denmark to be 2.2 cases per 100,000 people, with symptomatic AHP having a prevalence of 0.6 cases per 100,000 people.

“As reported internationally, AHP is more commonly diagnosed and symptomatic in women, and AIP was the most frequent AHP subtype,” the researchers wrote, adding that patients with high urinary PBG levels “were more likely to report AHP-related symptoms.”