Number needed to treat (NNT): implication in rheumatology clinical practice

Abstract

Objective: To calculate the number needed to treat (NNT) and number needed to harm (NNH) from the data in rheumatology clinical trials and systematic reviews. Methods: The NNTs for the clinically important outcome measures in the rheumatology systematic reviews from the Cochrane Library, issue 2, 2000 and in the original randomised, double blind, controlled trials were calculated. The measure used for calculating the NNT in rheumatoid arthritis (RA) interventions was the American College of Rheumatology 20% improvement or Paulus criteria; in osteoarthritis (OA) interventions, the improvement of pain; and in systemic sclerosis (SSc) interventions, the improvement of Raynaud's phenomenon. The NNH was calculated from the rate of withdrawals due to adverse events from the treatment. Results: The data required for the calculation of the NNT were available in 15 systematic reviews and 11 original articles. For RA interventions, etanercept treatment for six months had the smallest NNT (1.6; 95% confidence interval (CI) 1.4 to 2.0), whereas leflunomide had the largest NNH (9.6; 95% CI 6.8 to 16.7). For OA treatment options, only etodolac and tenoxicam produced significant pain relief compared with placebo (NNT=4.4; 95% CI 2.4 to 24.4 and 3.8; 95% CI 2.5 to 7.3, respectively). For SSc interventions, none were shown to be efficacious in improving Raynaud's phenomenon because the 95% CI of the NNT was infinite. Conclusions: The NNT and NNH are helpful for clinicians, enabling them to translate the results from clinical trials and systematic reviews to use in routine clinical practice. Both NNT and NNH should be accompanied by a limited 95% CI and adjusted for the individual subject's baseline risk.

Education, Self‐Management, and Upper Extremity Exercise Training in People With Rheumatoid Arthritis: A Randomized Controlled Trial

“…Because upper extremity disability is associated with global sensorimotor deficits in people with RA (), it is noteworthy that improvements in disability (d = 0.50; 95% CI 0.07, 0.93) following the EXTRA program appear greater than in studies that target single upper extremity joint complexes, although differing study outcomes hinder direct comparison (). Although there may be difficulties interpreting the clinical relevance of our findings, since MCIDs for many outcomes have not been established in an RA population, the change in DASH score following the EXTRA program is similar to the MCIDs reported in other chronic musculoskeletal conditions (4–15 DASH points) (), which were associated with increased work capacity () and the NNT comparable to rheumatology drug trials ().…”

Education, Self‐Management, and Upper Extremity Exercise Training in People With Rheumatoid Arthritis: A Randomized Controlled Trial

“…Because upper extremity disability is associated with global sensorimotor deficits in people with RA (), it is noteworthy that improvements in disability (d = 0.50; 95% CI 0.07, 0.93) following the EXTRA program appear greater than in studies that target single upper extremity joint complexes, although differing study outcomes hinder direct comparison (). Although there may be difficulties interpreting the clinical relevance of our findings, since MCIDs for many outcomes have not been established in an RA population, the change in DASH score following the EXTRA program is similar to the MCIDs reported in other chronic musculoskeletal conditions (4–15 DASH points) (), which were associated with increased work capacity () and the NNT comparable to rheumatology drug trials ().…”

Risk of tuberculosis with anti‐tumor necrosis factor‐α therapy: substantially higher number of patients at risk in Asia

“…Together, NNH and NNT allow physicians to compare different treatment options and outcomes for the same disease, enabling them to translate the results from clinical trials and systemic reviews for use in routine clinical practice. [25][26][27] The NNH due to anti-TNF-a therapy in our analysis was substantially lower in Asian countries (ranging from 8-2646) than previously published values in Western Europe (ranging from 232-6410). 15,24 Our study also indicates that the monoclonal antibody treatments adalimumab and infliximab had substantially lower NNH than the soluble TNF-a receptor fusion protein etanercept.…”

“…The NNT for using etanercept instead of adalimumab or infliximab provided the number of patients that need to be treated in order to prevent one event of TB. Together, NNH and NNT allow physicians to compare different treatment options and outcomes for the same disease, enabling them to translate the results from clinical trials and systemic reviews for use in routine clinical practice . The NNH due to anti‐TNF‐α therapy in our analysis was substantially lower in Asian countries (ranging from 8–2646) than previously published values in Western Europe (ranging from 232–6410) .…”

Antidepressants and the relief of osteoarthritic pain - Findings from a study examining adjunctive duloxetine

“…We recently published elsewhere a systematic review of duloxetine monotherapy for osteoarthritic pain (4). We quantified the clinical relevance of the statistically significant results from the 13‐week duloxetine studies using number needed to treat (NNT) and found that the NNT for duloxetine vs. placebo for treatment relief using a composite measure was six (95% CI 4–10), which overlaps with the 95% CI observed with the NNT for response for other treatments, such as etodolac after 4 weeks (NNT 5, 95% CI 3–25) and tenoxicam after 8 weeks (NNT 4, 94% CI 3–8), as calculated in systematic reviews for OA (5). Of interest is that amelioration in pain was not dependent on improvement in depressive symptoms (4).…”

Education, Self‐Management, and Upper Extremity Exercise Training in People With Rheumatoid Arthritis: A Randomized Controlled Trial

“…Because upper extremity disability is associated with global sensorimotor deficits in people with RA (), it is noteworthy that improvements in disability (d = 0.50; 95% CI 0.07, 0.93) following the EXTRA program appear greater than in studies that target single upper extremity joint complexes, although differing study outcomes hinder direct comparison (). Although there may be difficulties interpreting the clinical relevance of our findings, since MCIDs for many outcomes have not been established in an RA population, the change in DASH score following the EXTRA program is similar to the MCIDs reported in other chronic musculoskeletal conditions (4–15 DASH points) (), which were associated with increased work capacity () and the NNT comparable to rheumatology drug trials ().…”

Risk of tuberculosis with anti‐tumor necrosis factor‐α therapy: substantially higher number of patients at risk in Asia

“…Together, NNH and NNT allow physicians to compare different treatment options and outcomes for the same disease, enabling them to translate the results from clinical trials and systemic reviews for use in routine clinical practice. [25][26][27] The NNH due to anti-TNF-a therapy in our analysis was substantially lower in Asian countries (ranging from 8-2646) than previously published values in Western Europe (ranging from 232-6410). 15,24 Our study also indicates that the monoclonal antibody treatments adalimumab and infliximab had substantially lower NNH than the soluble TNF-a receptor fusion protein etanercept.…”

“…The NNT for using etanercept instead of adalimumab or infliximab provided the number of patients that need to be treated in order to prevent one event of TB. Together, NNH and NNT allow physicians to compare different treatment options and outcomes for the same disease, enabling them to translate the results from clinical trials and systemic reviews for use in routine clinical practice . The NNH due to anti‐TNF‐α therapy in our analysis was substantially lower in Asian countries (ranging from 8–2646) than previously published values in Western Europe (ranging from 232–6410) .…”

Antidepressants and the relief of osteoarthritic pain - Findings from a study examining adjunctive duloxetine

“…We recently published elsewhere a systematic review of duloxetine monotherapy for osteoarthritic pain (4). We quantified the clinical relevance of the statistically significant results from the 13‐week duloxetine studies using number needed to treat (NNT) and found that the NNT for duloxetine vs. placebo for treatment relief using a composite measure was six (95% CI 4–10), which overlaps with the 95% CI observed with the NNT for response for other treatments, such as etodolac after 4 weeks (NNT 5, 95% CI 3–25) and tenoxicam after 8 weeks (NNT 4, 94% CI 3–8), as calculated in systematic reviews for OA (5). Of interest is that amelioration in pain was not dependent on improvement in depressive symptoms (4).…”

Education, Self‐Management, and Upper Extremity Exercise Training in People With Rheumatoid Arthritis: A Randomized Controlled Trial

“…Because upper extremity disability is associated with global sensorimotor deficits in people with RA (), it is noteworthy that improvements in disability (d = 0.50; 95% CI 0.07, 0.93) following the EXTRA program appear greater than in studies that target single upper extremity joint complexes, although differing study outcomes hinder direct comparison (). Although there may be difficulties interpreting the clinical relevance of our findings, since MCIDs for many outcomes have not been established in an RA population, the change in DASH score following the EXTRA program is similar to the MCIDs reported in other chronic musculoskeletal conditions (4–15 DASH points) (), which were associated with increased work capacity () and the NNT comparable to rheumatology drug trials ().…”

Risk of tuberculosis with anti‐tumor necrosis factor‐α therapy: substantially higher number of patients at risk in Asia

“…Together, NNH and NNT allow physicians to compare different treatment options and outcomes for the same disease, enabling them to translate the results from clinical trials and systemic reviews for use in routine clinical practice. [25][26][27] The NNH due to anti-TNF-a therapy in our analysis was substantially lower in Asian countries (ranging from 8-2646) than previously published values in Western Europe (ranging from 232-6410). 15,24 Our study also indicates that the monoclonal antibody treatments adalimumab and infliximab had substantially lower NNH than the soluble TNF-a receptor fusion protein etanercept.…”

“…The NNT for using etanercept instead of adalimumab or infliximab provided the number of patients that need to be treated in order to prevent one event of TB. Together, NNH and NNT allow physicians to compare different treatment options and outcomes for the same disease, enabling them to translate the results from clinical trials and systemic reviews for use in routine clinical practice . The NNH due to anti‐TNF‐α therapy in our analysis was substantially lower in Asian countries (ranging from 8–2646) than previously published values in Western Europe (ranging from 232–6410) .…”

Antidepressants and the relief of osteoarthritic pain - Findings from a study examining adjunctive duloxetine

“…We recently published elsewhere a systematic review of duloxetine monotherapy for osteoarthritic pain (4). We quantified the clinical relevance of the statistically significant results from the 13‐week duloxetine studies using number needed to treat (NNT) and found that the NNT for duloxetine vs. placebo for treatment relief using a composite measure was six (95% CI 4–10), which overlaps with the 95% CI observed with the NNT for response for other treatments, such as etodolac after 4 weeks (NNT 5, 95% CI 3–25) and tenoxicam after 8 weeks (NNT 4, 94% CI 3–8), as calculated in systematic reviews for OA (5). Of interest is that amelioration in pain was not dependent on improvement in depressive symptoms (4).…”