Age and paracetamol self-poisoning

Abstract

Background: Whereas paracetamol poisoning is predominantly seen in adolescents and young adults, the majority of paracetamol associated deaths occur in an older population.

Aims: The aim of the present study was to evaluate age as a risk factor for fulminant hepatic failure (FHF) and death in a large population of patients with paracetamol poisoning.

Patients: A total of 746 patients transferred to a specialised unit with severe paracetamol poisoning and 273 unselected patients admitted from the local region over a 10 year period.

Methods: A partly retrospective study based on hospital charts. The risk associated with age was evaluated by multivariate analysis.

Results: Paracetamol poisoning most frequently occurred in the age group 15-24 years. Transferred patients were significantly older than local patients (median age 37 years v 29 years; p = 0.0006). In contrast, FHF and death from paracetamol poisoning most frequently occurred in patients aged 40 years or above. In a logistic regression analysis, "age >/=40 years" was associated with an excess risk of FHF (odds ratio (OR) 2.33 (95% confidence interval (CI) 1.50-3.64)) and death or liver transplantation (OR 4.18 (95% CI 2.17-8.05)). In addition, older age was associated with other risk factors for paracetamol hepatotoxicity such as regular alcohol abuse and late presentation.

Conclusions: Age 40 years or above was identified as a significant independent risk factor for FHF and mortality following paracetamol overdose. Patients aged 40 years or above should be considered as high risk patients, in particular when older age appears in combination with regular alcohol abuse or late presentation.

Figure 1

Age and sex specific distributions normalised as a percentage among 273 unselected patients (A) admitted from the local region with predominantly uncomplicated paracetamol poisoning and among 746 patients transferred (B) with signs of paracetamol induced liver injury.

Figure 2

Age distribution among 170 transferred patients with paracetamol induced liver failure with indications of death and orthotopic liver transplantation (OLT).

Figure 3

Age specific risk of liver failure (A) and death or orthotopic liver transplantation (OLT) (B) among 746 patients transferred with signs of severe paracetamol intoxication. Whiskers indicate 95% confidence interval.

Figure 4

Age specific prevalence of regular alcohol abuse among 746 patients transferred with signs of severe paracetamol intoxication. Whiskers indicate 95% confidence interval.

Figure 5

Age specific distribution of time from paracetamol ingestion to initiation of N-acetylcysteine therapy in 746 patients transferred with signs of severe paracetamol intoxication. Plot indicates median and interquartile range (whiskers).

Figure 6

Age specific risk of liver failure (A) and death or liver transplantation (OLT) (B) among 746 patients transferred with signs of severe paracetamol intoxication divided into four subgroups by regular alcohol abuse (absent or present) and time of N-acetylcysteine treatment (early (that is, <24 hours) or late (that is, >24 hours)). Whiskers indicate 95% confidence interval.