abstract
BACKGROUND:
Cancer
pain is an important and distressing symptom that tends to increase in
frequency and intensity as the cancer advances. For people with advanced
cancer, the prevalence of pain can be as high as 90%. It has been
estimated that 30% to 50% of people with cancer categorise their pain as
moderate to severe, with between 75% and 90% of people with cancer
experiencing pain that they describe as having a major impact on their
daily life. Epidemiological studies suggest that approximately 15% of
people with cancer pain fail to experience acceptable pain relief with
conventional management. Uncontrolled pain can lead to physical and
psychological distress and can, consequently, have a drastic effect on
people's quality of life.
OBJECTIVES:
To
determine the analgesic efficacy of hydromorphone in relieving cancer
pain, as well as the incidence and severity of any adverse events.
SEARCH METHODS:
We
searched the Cochrane Central Register of Controlled Trials, MEDLINE,
Embase and clinical trials registers up to
April 2016. There were no
language, document type or publication status limitations applied in the
search.
SELECTION CRITERIA:
We
included randomised controlled trials (RCTs) that compared
hydromorphone with placebo or other active pain medication for cancer
pain in both adults and children. The four main outcomes selected have
previously been identified as important to people with cancer; pain no
worse than mild pain, and the impact of the treatment on consciousness,
appetite and thirst. We did not consider physician-, nurse- or
carer-reported measures of pain.
DATA COLLECTION AND ANALYSIS:
Two
review authors independently extracted data. For binary outcomes, we
calculated risk ratio (RR) and its 95% confidence interval (CI), on an
intention-to-treat basis. For continuous data, we estimated the mean
difference (MD) between groups and its 95% CI. We used a random-effects
model and assessed the risk of bias for all included studies. A
meta-analysis was not completed on any of the primary outcomes in this
review due to the lack of data. We assessed the evidence using GRADE and
created two 'Summary of findings' tables.
MAIN RESULTS:
We
included four studies (604 adult participants), which compared
hydromorphone to oxycodone (two studies) or morphine (two studies).
Overall, the included studies were at low or unclear risk of bias, rated
unclear due to unknown status of blinding of outcome assessment; we
rated three studies at high risk of bias for potential conflict of
interest. Data for 504 participants were available for analysis. We
collected data on endpoint participant-reported pain intensity measured
with a visual analogue scale (VAS) (mean ± standard deviation (SD):
hydromorphone 28.86 ± 17.08, n = 19; oxycodone 30.30 ± 25.33, n = 12;
scale from 0 to 100 with higher score indicating worse pain), and Brief
Pain Inventory (BPI) 24 hours worst pain subscale (mean ± SD:
hydromorphone 3.5 ± 2.9, n = 99; morphine 4.3 ± 3.0, n = 101, scale from
0 to 10 with higher score indicating worse pain). The data demonstrated
a similar effect between groups with both comparisons. The pain
intensity data showed that participants in all four trials achieved no
worse than mild pain. There were several adverse events: some were the
expected opioid adverse effects such as nausea, constipation and
vomiting; others were not typical opioid adverse effects (for example,
decreased appetite, dizziness and pyrexia, as shown in Table 1 in the
main review), but generally showed no difference between groups. There
were three deaths in the morphine group during the trial period,
considered to be due to disease progression and unrelated to the drug.
Three trials had over 10% dropout, but the reason and proportion of
dropout was balanced between groups. The overall quality of evidence was
very low mainly due to high risk of bias, imprecision of effect
estimates and publication bias. There were no data available for
children or for several participant-important outcomes, including
participant-reported pain relief and treatment impact on consciousness,
appetite or thirst.
AUTHORS' CONCLUSIONS:
This
review indicated little difference between hydromorphone and other
opioids in terms of analgesic efficacy. Data gathered in this review
showed that hydromorphone had a similar effect on participant-reported
pain intensity as reported for oxycodone and morphine. Participants
generally achieved no worse than mild pain after taking hydromorphone,
which is comparable with the other drugs. It produced a consistent
analgesic effect through the night and could be considered for use in
people with cancer pain experiencing sleep disturbance. However, the
overall quality of evidence was very low mainly due to risk of bias,
imprecision of effect estimates and publication bias. This review only
included four studies with limited sample size and a range of study
designs. Data for some important outcomes, such as impact of the
treatment on consciousness, appetite or thirst, were not available.
Therefore, we were unable to demonstrate superiority or inferiority of
hydromorphone in comparison with other analgesics for these outcomes. We
recommend that further research with larger sample sizes and more
comprehensive outcome data collection is required.
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