Objective:

The aim of this study was to evaluate the prevalence of breakthrough pain (BTP) in ambulatory patients with non-cancer chronic pain in Spain and to characterize physiopathology, location, intensity and frequency of BTP episodes.

Methods:

Prospective, non-interventional, observational study conducted in 16 pain units of hospitals of Andalusia and Ceuta. Eligible consecutive patients were are asked if they experience BTP defined as "a transient exacerbation of pain that occurs either spontaneously, or in relation to a specific predictable or unpredictable trigger, despite stable and controlled background pain". At each survey day, the first two patients reporting BTP were further interrogated on the clinical characteristics of their BTP (etiology, onset, intensity, frequency and treatment).

Results:

A total of 3,209 patients with non-cancer chronic pain were screened to identify 1,118 patients with BTP, which represented a prevalence of 36 %. BTP characteristics were retrieved from 350 patients: mean BTP intensity was 8.3 (± 1.4) on a Visual Analogue Scale (VAS), with a mean of 2 episodes/24 hour (range 1-5/24 h). Pain mechanism was mixed in 149 (42.6 %), neuropathic in 91 (26 %) and nociceptive in 72 in (20.6 %) of patients. Significant correlation was found between BTP intensity and both higher background pain (r = 0.243, p < 0.001), and daily BTP episodes frequency (r = 0.123, p = 0.003). 78 % of the patients were on opioid treatment. The most frequent were fentanyl citrate (52.6 %) and tramadol (17.4 %).

Conclusions:

The prevalence rate of BTP in patients with chronic non-oncologic pain is higher than one-third of the patients seen in outpatient hospital pain units in Spain. BTP causes reduced levels of functionality, psychological disorders, and an increase in health care expenditure. Individualization is the key to treatment.

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