Trial Outcomes & Findings for Chronic Low Back Pain Research Project (NCT NCT00108550)

Last Updated: 2014-02-10

Results Overview

Self-report measure of "current" pain intensity of chronic back pain. Participants rate pain on a 20 point scale as being greater or less intense relative to 12 adjectival descriptor word anchors (eg, greater or less than "faint," "moderate," "strong"). Scores range from 0 to 20 with higher scores indicating higher pain intensity. Prior to analysis an order-preserving mean-matching variance-stabilizing transformation was applied to this measure placing it on a continuous 0-1.5 scale. The single values reported below represent adjusted means of transformed pain intensity over all time points.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

108 participants

Primary outcome timeframe

Baseline to Week 12 with Interim Measurement at Weeks 1, 2, 3, 4, 5, 7 and 9

Results posted on

2014-02-10

Participant Flow

Dates of recruitment were January 2005 to June 2009 by newsprint advertisements to the general community, by word-of-mouth, and posting of flyers at primary care clinics at two performance sites (VA San Diego Healthcare System and University of Califonia Medical Center, San Diego).

Participant milestones

Participant milestones
Measure	Gabapentin gabapentin capsule 1200mg three times a day for 12 weeks	Placebo Inert placebo capsules, 3 capsules three times a day for 12 weeks
Overall Study STARTED	55	53
Overall Study COMPLETED	39	37
Overall Study NOT COMPLETED	16	16

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Chronic Low Back Pain Research Project

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Gabapentin n=55 Participants gabapentin capsule 1200mg three times a day for 12 weeks	Placebo n=53 Participants Inert placebo capsules, 3 capsules three times a day for 12 weeks	Total n=108 Participants Total of all reporting groups
Age, Continuous	57.40 years STANDARD_DEVIATION 8.88 • n=5 Participants	54.62 years STANDARD_DEVIATION 11.38 • n=7 Participants	56.04 years STANDARD_DEVIATION 10.23 • n=5 Participants
Sex: Female, Male Female	10 Participants n=5 Participants	13 Participants n=7 Participants	23 Participants n=5 Participants
Sex: Female, Male Male	45 Participants n=5 Participants	40 Participants n=7 Participants	85 Participants n=5 Participants
Region of Enrollment United States	55 participants n=5 Participants	53 participants n=7 Participants	108 participants n=5 Participants

PRIMARY outcome

Timeframe: Baseline to Week 12 with Interim Measurement at Weeks 1, 2, 3, 4, 5, 7 and 9

Population: Analysis of all randomized participants receiving study drug

Outcome measures

Outcome measures
Measure	Placebo n=53 Participants Inert placebo capsules, 3 capsules three times a day for 12 weeks	Gabapentin n=55 Participants gabapentin capsule 1200mg three times a day for 12 weeks
Transformed Descriptor Differential Scale-Pain Intensity Scores Adjusted for Time	0.6683 units on a scale Interval 0.6145 to 0.722	0.6988 units on a scale Interval 0.6463 to 0.7512

SECONDARY outcome

Timeframe: Baseline to Week 12 with Interim Measurement at Weeks 1, 2, 3, 4, 5, 7 and 9

Population: Randomized participants who received one dose of study drug

This questionnaire measures disability in everyday function due to back pain. It is a 24-item checklist asking patients to endorse whether or not back pain limits activities they normally do (eg, "I stay at home most of the time because of my back"). Scores range from 0 to 24, with higher scores indicating greater disability in everyday function due to back pain. The single values reported below represent adjusted means of scores over all time points.

Outcome measures

Outcome measures
Measure	Placebo n=53 Participants Inert placebo capsules, 3 capsules three times a day for 12 weeks	Gabapentin n=55 Participants gabapentin capsule 1200mg three times a day for 12 weeks
Roland and Morris Disability Index Scores Adjusted for Time	7.50 units on a scale 95% Confidence Interval 4.30 • Interval 6.47 to 8.52	6.96 units on a scale 95% Confidence Interval 3.53 • Interval 5.95 to 7.97

Adverse Events

Placebo

Serious events: 0 serious events

Other events: 21 other events

Deaths: 0 deaths

Gabapentin

Serious events: 0 serious events

Other events: 42 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Additional Information

J. H. Atkinson MD

VA San Diego Healthcare System

Phone: 858-642-3775

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place

Other adverse events
Measure	Placebo n=53 participants at risk Inert placebo capsules, 3 capsules three times a day for 12 weeks	Gabapentin n=55 participants at risk gabapentin capsule 1200mg three times a day for 12 weeks
Nervous system disorders sleepiness	26.4% 14/53 • Number of events 14 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	52.7% 29/55 • Number of events 29 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Nervous system disorders asthenia/fatigue	28.3% 15/53 • Number of events 15 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	49.1% 27/55 • Number of events 27 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Cardiac disorders orthostatic dizziness	26.4% 14/53 • Number of events 14 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	43.6% 24/55 • Number of events 24 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Gastrointestinal disorders decreased salivation	18.9% 10/53 • Number of events 10 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	40.0% 22/55 • Number of events 22 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Nervous system disorders increased sleep	20.8% 11/53 • Number of events 11 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	38.2% 21/55 • Number of events 21 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Nervous system disorders concentration difficulties	11.3% 6/53 • Number of events 6 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	38.2% 21/55 • Number of events 21 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Eye disorders accomodation disturbance	5.7% 3/53 • Number of events 3 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	34.5% 19/55 • Number of events 19 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Nervous system disorders loss of balance	3.8% 2/53 • Number of events 2 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	32.7% 18/55 • Number of events 18 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Nervous system disorders reduced sleep	18.9% 10/53 • Number of events 10 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	12.7% 7/55 • Number of events 7 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Gastrointestinal disorders constipation	17.0% 9/53 • Number of events 9 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	12.7% 7/55 • Number of events 7 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Gastrointestinal disorders nausea	15.1% 8/53 • Number of events 8 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	12.7% 7/55 • Number of events 7 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
General disorders polyuria/polydipsia	11.3% 6/53 • Number of events 6 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	12.7% 7/55 • Number of events 7 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Gastrointestinal disorders diarrhea	13.2% 7/53 • Number of events 7 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	10.9% 6/55 • Number of events 6 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Nervous system disorders increased dreaming	9.4% 5/53 • Number of events 5 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	9.1% 5/55 • Number of events 5 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Nervous system disorders failing memory	1.9% 1/53 • Number of events 1 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	16.4% 9/55 • Number of events 9 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Reproductive system and breast disorders erectile dysfunction	3.8% 2/53 • Number of events 2 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	10.9% 6/55 • Number of events 6 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Reproductive system and breast disorders decreased sexual desire	3.8% 2/53 • Number of events 2 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	9.1% 5/55 • Number of events 5 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
General disorders weight gain	1.9% 1/53 • Number of events 1 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	10.9% 6/55 • Number of events 6 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Renal and urinary disorders micturation disturbance	7.5% 4/53 • Number of events 4 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	3.6% 2/55 • Number of events 2 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Nervous system disorders anxiety	1.9% 1/53 • Number of events 1 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	9.1% 5/55 • Number of events 5 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Nervous system disorders headache	3.8% 2/53 • Number of events 2 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	5.5% 3/55 • Number of events 3 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.
Nervous system disorders paresthesia	5.7% 3/53 • Number of events 3 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.	3.6% 2/55 • Number of events 2 • Participant report of adverse effects at any point during the 12-week trial. A psychiatrist-administered, semi-structured interview (Scandinavian Society of Psychopharmacological Investigators Side Effect Rating Scale, UKU), assessed 48 psychotropic drug-associated symptoms in the prior 3 days. Items rated as "present" (of at least "mild" intensity) and "possibly" or "probably" drug-induced were counted as adverse effects.