| Study | Reason for exclusion |
|---|---|
| Allegrini 2009 | NSAIDs used in both groups, comparison concerned only the mode of administration of the same NSAID (piroxicam patch versus cream) |
| Altan 2019 | NSAIDs were not evaluated separately: a combination of NSAIDs and myorelaxants was evaluated |
| Anaya 2014 | Not a RCT; clinical series |
| Arul Prakasam 2011 | Not a RCT; prospective study, no randomisation |
| Berry 1988 | NSAIDs used in both groups; only addition of muscle relaxant evaluated |
| Blazek 1986 | No acute LBP; sciatica |
| Borenstein 1990 | NSAIDs used in both groups; only addition of muscle relaxant evaluated |
| Bruggemann 1990 | NSAIDs used in both groups; only addition of vitamins B1/B6/B12 evaluated |
| Buchbinder 2010 | No RCT; commentary on Cochrane Review |
| Chrubasik 2003 | No acute LBP; chronic LBP in flare |
| Coats 2004 | No acute LBP; chronic LBP in flare |
| Cohen 2017 | The pharmacotherapy group could use different types of medication; no subgroup analysis of NSAID users |
| Costantino 2011 | NSAIDs used in both groups, comparison concerned only the way of administration (mesotherapeutic versus systemic administration) |
| Day 2013 | No RCT; case report and review |
| Dehghan 2014 | NSAIDs were used in all three groups, no comparison group without NSAIDs. Only addition of thermotherapy or cryotherapy evaluated |
| Dehghan 2015 | NSAIDs were used in both groups, no comparison group without NSAIDs. Only addition of gabapentin evaluated |
| Driessens 1994 | No acute LBP; chronic LBP |
| Eken 2014 | No relevant timing of outcome assessments, follow‐up time 30 minutes (minimum follow‐up time for this systematic review is 1 day) |
| Evans 1980 | No acute LBP; chronic LBP in flare |
| Friedman 2015 | NSAIDs were used in all three groups, no comparison group without NSAIDs. Only addition of either cyclobenzaprine or oxycodone/acetaminophen evaluated |
| Friedman 2016 | NSAIDs were used in both groups, no comparison group without NSAIDs. Only addition of diazepam versus placebo evaluated |
| Friedman 2018 | NSAIDs were used in all three groups, no comparison group without NSAIDs. Only addition of either orphenadrine or methocarbamol versus placebo evaluated. |
| Geller 2016 | NSAIDs were used in both groups, no comparison group without NSAIDs. Only addition of B vitamins evaluated. |
| Górska 2005 | NSAIDs used in both groups; no comparison group without NSAIDs. Only addition of muscle relaxant evaluated. |
| Ilic 2009 | NSAIDs used in both groups; comparison concerned two generic formulations of the same NSAID (nimesulide). |
| Ingpen 1969 | No acute LBP; chronic LBP |
| IRCT2013052213146N2 | NSAIDs were used in all groups, no comparison group without NSAIDs. |
| Kuhlwein 1990 | NSAIDs used in both groups; only addition of vitamins B1/B6/B12 evaluated. |
| Lee 2008 | No relevant timing of outcome assessments, follow‐up time 1 hour (minimum follow‐up time for this systematic review was 1 day). |
| Listrat 1990 | NSAIDs used in both groups, comparison concerned only the mode of administration of the same NSAID (tenoxicam tablets versus intramuscular injections). |
| Matsumo 1981 | No acute LBP; chronic LBP |
| Muckle 1986 | No acute LBP; acute lumbar disc syndrome with an affected nerve root |
| Ostojic 2017 | NSAIDs were used both groups, no comparison group without NSAIDs. Only addition of paracetamol evaluated. |
| Pena 1990 | Information derived from a review. The original trial of Bontoux was not found. The reported data were not sufficient to be part of the current review. |
| Schreijenberg 2017 | No study results available. Study was terminated early because of low recruitment rates. |
| Serinken 2016 | No relevant timing of outcome assessments, follow‐up time 30 minutes (minimum follow‐up time for this systematic review was 1 day). NSAIDs used in both groups, only additional topical NSAID gel vs placebo tested. |
| Shell 2012 | No acute LBP; chronic LBP lasting > 6 weeks, confirmed by corresponding author. |
| Shikhkerimov 2016 | Not a RCT |
| Siegmeth 1978 | No LBP; radiologically confirmed lumbar osteoarthritis. Presence and duration of LBP was not mentioned. |
| Stark 2014 | Oral NSAIDs were included for blinding purposes only (N = 5). |
| Vetter 1988 | NSAIDs were used in both groups, no comparison group without NSAIDs. |
| Voicu 2019 | A combination of medication was used; NSAIDs were not evaluated separately. |
| von Uberall 2013 | Not a RCT; secondary analysis on 4 non‐interventional studies on NSAIDs. |
| Yastrebov 2012 | Not a RCT; no randomisation, intense lumbar pain syndrome, LBP not specifically mentioned. |
NSAID = non‐steroidal anti‐inflammatory drug; LBP = low back pain; RCT = randomised controlled trial