Cochrane · intervention · CD010470
Interventions for managing taste disturbances
Kumbargere Nagraj, S, George, RP, Shetty, N, et al. · Cochrane Database of Systematic Reviews · 2017 · Cochrane Library
Full textEvery question was extracted from the full review (methods and results), not only its Summary of Findings table.
Questions
15
current version
GRADE rated
7
No studies
3
Included studies
10
as reported
No studies 3 · 20%Ungraded 5 · 33.3%Very low 7 · 46.7%Low 0 · 0%Moderate 0 · 0%High 0 · 0%
Ungraded means an effect was reported without a GRADE rating; it is not a gap. No studies means the review found nothing to answer the question. The six categories are a display order, not a score.
Review question
| Element | Planned (methods) | Found (results) |
|---|---|---|
| Population | Patients with taste disorders diagnosed clinically as dysgeusia, parageusia, ageusia, hypogeusia or phantogeusia regardless of age, gender, race, profession or residential location. Exclusions: demolitive surgery of tongue/palate/oropharynx; oral lesions (ulcers, stomatitis, candidiasis, necrosis); cerebral lesions or surgical damage to the nervous system; endocrinal/neurological disorders affecting taste or smell; drugs affecting taste perception (e.g. chemotherapy); treatment affecting salivary function (e.g. radiotherapy); hyposalivation | 581 participants across 10 trials (566 in the quantitative analyses); taste disorders that were idiopathic, zinc-deficiency-induced, or secondary to chronic renal failure; eight adult trials and two paediatric trials; age range 0.5 to 83 years; sample sizes 15 to 219 |
| Intervention | Any intervention (pharmacological or non-pharmacological) versus placebo or no treatment; any direct comparison between two active interventions (e.g. drug A vs drug B, or two doses of the same drug); all routes of administration or modes of application | Zinc sulphate (n=3); Zinc acetate (n=2); Polaprezinc (n=2); Zinc picolinate (n=1); Zinc gluconate (n=1); Acupuncture (n=1) |
| Comparison | Placebo; no treatment; another active intervention (direct comparison) | Placebo (n=9); Sham acupuncture (n=1) |
| Outcomes | Primary: taste acuity improvement to at least one quality of taste by subjective/objective assessment scales; taste discrimination improvement. Secondary: adverse events related to the interventions; health-related quality of life | Taste acuity improvement - patient-reported (n=119); Taste acuity improvement - objective continuous (n=366); Taste acuity improvement - objective continuous taste detection (n=14); Taste acuity improvement - objective continuous taste recognition (n=14); Taste acuity improvement - objective continuous individual taste sensations (n=22); Taste acuity improvement - objective dichotomous, idiopathic/zinc-deficient (n=292); Taste acuity improvement - objective dichotomous, chronic renal failure (n=24); Adverse events (n=335); Taste discrimination - zinc (Matson 2003, not analysable); Taste discrimination - acupuncture (n=37); Health-related quality of life (narrative) |
| Study designs | Parallel and cross-over randomised controlled trials (RCTs), pharmacological or non-pharmacological; quasi-RCTs excluded | Parallel RCTs (n=8); Cross-over RCTs (n=2) |
| Timing | Not specified | Zinc supplementation trials mean ~3 months (adverse events follow-up 12 to 18 weeks; cross-over trial 6 months); acupuncture trial eight weeks |
Search date: 2017-07. Databases: Cochrane Oral Health's Trials Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE Ovid; Embase Ovid; CINAHL EBSCO; AMED Ovid; US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov); WHO International Clinical Trials Registry Platform (ICTRP);…
Questions and results
Show all 3 versionsZinc supplements (zinc sulphate, zinc gluconate, zinc picolinate, zinc acetate, or polaprezinc) vs Placebo
Population: Patients with taste disturbances (dysgeusia/hypogeusia; idiopathic, zinc-deficient, or secondary to chronic renal failure)
| Outcome | Effect | Evidence | Status / GRADE |
|---|---|---|---|
Taste acuity improvement - objective outcome (continuous) - taste detection (cross-over trial) 6 months · Children with chronic renal failure | MD 2.50 [0.93, 4.07] Mean taste detection 7.5 (placebo) vs MD 2.50 higher | 1 study · 14 participants | Very low Downgraded: risk of bias, imprecision, publication bias |
Health-related quality of life | Results (health-related quality of life): None of the studies reported data on health-related quality of life. Heckmann 2005 (zinc) reported that signs of depression were less severe (Beck Depression Inventory P<0.05;… | 1 study | Ungraded |
Taste acuity improvement - patient-reported outcome Mean 3 months · Zinc-deficient/idiopathic taste disorder | RR 1.40 [0.94, 2.09] 407 per 1000 (study population) vs 569 per 1000 | 2 studies · 119 participants | Very low Downgraded: risk of bias, imprecision, publication bias |
Taste acuity improvement - objective outcome (continuous) - individual taste sensations Chronic renal failure | Results (Mahajan 1980, chronic renal failure; Analysis 1.3): mean difference by taste sensation - salt MD 285 (95% CI 238.75 to 331.25); sweet MD 190 (142.36 to 237.64); sour MD 10 (-16.43 to 36.43); bitter MD 2.40… | 1 study · 22 participants | Ungraded |
Taste discrimination improvement | Results: Matson 2003 used zinc sulphate for testing taste discrimination (sip and spit method); the trial did not report the details of the placebo group and thus the results could not be meta-analysed. Not GRADE-rated. | 1 study | Ungraded |
Taste acuity improvement - objective outcome (continuous) - taste recognition (cross-over trial) 6 months · Children with chronic renal failure | MD 3.00 [0.66, 5.34] Mean taste recognition 16 (placebo) vs MD 3.00 higher | 1 study · 14 participants | Very low Downgraded: risk of bias, imprecision, publication bias |
Taste acuity improvement - objective outcome (dichotomous) - chronic renal failure Chronic renal failure | RR 25 [1.65, 379.57] | 1 study · 24 participants | Ungraded |
Taste acuity improvement - objective outcome (continuous data) Mean 3 months · Idiopathic dysgeusia | SMD 0.44 [0.23, 0.65] | 3 studies · 366 participants | Very low Downgraded: risk of bias, imprecision, publication bias |
Adverse events 12 to 18 weeks | RR 5.20 [0.90, 30.19] 6 per 1000 vs 31 per 1000 | 3 studies · 335 participants | Very low Downgraded: risk of bias, imprecision, publication bias |
Taste acuity improvement - objective outcome (dichotomous data) Mean 3 months · Idiopathic/zinc-deficient taste disorder | RR 1.42 [1.09, 1.84] 435 per 1000 (study population) vs 618 per 1000 | 2 studies · 292 participants | Very low Downgraded: risk of bias, imprecision, publication bias |
Acupuncture vs Sham control (deactivated laser sham acupuncture)
Population: Patients with idiopathic dysgeusia and hypogeusia
| Outcome | Effect | Evidence | Status / GRADE |
|---|---|---|---|
Taste discrimination improvement 8 weeks | MD 2.80 [-1.18, 6.78] Mean taste discrimination 14.7 (sham) vs MD 2.80 higher | 1 study · 37 participants | Very low Downgraded: risk of bias, imprecision |
Health-related quality of life | Results (health-related quality of life): Brandt 2008 assessed HRQoL in dysgeusia patients and reported significant improvement in psychological symptoms in the acupuncture group and increased quality of life in both… | 1 study | Ungraded |
Adverse events | Results: The acupuncture trial (Brandt 2008) did not give any data on adverse events in either group. | 0 studies | No studies |
Taste acuity improvement | Results: There were no data on taste acuity improvement in the included acupuncture trial (Brandt 2008). | 0 studies | No studies |
Zinc supplements vs Acupuncture
Population: Patients with taste disturbances (dysgeusia/hypogeusia; idiopathic, zinc-deficient, or secondary to chronic renal failure)
| Outcome | Effect | Evidence | Status / GRADE |
|---|---|---|---|
Outcome NR | Authors' conclusions: We were unable to draw any conclusions regarding the superiority of zinc supplements or acupuncture as none of the trials compared these interventions. | 0 studies | No studies |