Validity of Referral Hospitals for the Toxicovigilance of Acute Poisoning in Sri Lanka/Validite Des Hopitaux De Reference Concernant la Toxicovigilance Des Intoxications Aigues Au Sri Lanka/Validez De Los Hospitales De Derivacion Para la Toxicovigilancia De Intoxicaciones Agudas En Sri Lanka

Article excerpt

Introduction

Death from acute poisoning is a major public health issue in many countries. Most deaths are from self-poisoning with highly toxic pesticides, which globally account for the overwhelming majority of poisoning deaths and around one third of all suicides. (1) The problem is most widespread in rural areas of developing countries. (2,3) This is true of Sri Lanka, where poisoning is among the top five causes of in-hospital deaths in rural areas. (4,5) Although acute poisoning can be either intentional or accidental, Sri Lankan hospitals see few accidental poisonings and almost all admissions are due to deliberate self-poisoning. (6,7)

Continuous surveillance of cases of acute poisoning is important for planning and evaluating public health interventions. However, the methods required for such surveillance are potentially complicated, since the majority of poisoned patients present to small primary hospitals for initial assessment and care and are later transferred to secondary (referral) hospitals. (8) To date, most epidemiological studies in Sri Lanka have been performed in these larger referral hospitals, (9) as have nearly all hospital studies used to estimate pesticide poisoning rates elsewhere in the world. (1) Such studies may be subject to various forms of selection bias. On the other hand, official government statistics are usually a sum of the admission statistics from all hospitals. Since existing surveillance systems rarely allow data linkage to track patients transferred from primary to referral hospitals, transferred patients end up being counted twice. This obviously creates a bias that can result, for example, in an underestimation of the case-fatality rate. (8) Hence, it is important, especially in the developing world, to identify a good but uncomplicated strategy for accurately collecting data on acute poisonings and to estimate the magnitude and direction of the systematic bias inherent in various data collection methods. The objective of our study was to explore which of three different data collection methods could deliver the most accurate estimates of the incidence of acute poisoning in a rural district of Sri Lanka.

Methods

For 17 consecutive months we collected data on all admissions of acutely poisoned patients to all hospitals with inpatient beds in Anuradhapura, a large rural district in Sri Lanka's North Central Province. This included 34 primary hospitals and one referral hospital.

The data were collected as part of a cluster-randomized controlled trial (ISRCTN73983810) that was designed to assess the effect of a brief educational intervention about the management of poisoned patients in primary hospitals. The study established data linkage between the primary and referral hospitals to enable the follow-up of all transferred patients and validate the primary hospital medical record by means of direct interviews with transferred patients.

Anuradhapura district had a total of 820000 inhabitants, 631715 of which were above the age of 12 years in mid 2009. The district's land area represents about 11% of the national territory. (10) Demographically and socioeconomically its population is representative of rural Sri Lanka, and so are its health-care services. (10,11)

All public hospitals with inpatient facilities in the district were included in the study. The 34 primary hospitals are the first point of health system contact for the majority of poisoned patients, many of whom are then transferred to the referral hospital, which has an intensive care unit with specialized staff and better stocks of antidotes and medication.

The region has four small private hospitals, all of which were excluded from the study because they indicated that they never provided care for poisoned patients.

We collected data on all patients who were 12 years of age or older and who were admitted into study hospitals for acute poisoning from 1 September 2008 to 30 January 2010. …