Het volume van chirurgische ingrepen en de impact ervan op ... - KCE

More documents

Recommendations

Info

10 Volume Outcome KCE reports 113 MAIN FINDINGS This section summarizes the results of the SR in relation to the volume outcome association. These results are given for each outcome variable, and, when possible, for hospital volume and surgeon volume separately. For reasons of feasibility we simplified the results into four possible conclusions on this volume outcome association. 1. Direct or positive VOA when volume and outcome move in the same direction i.e. better outcome in high-volume hospitals or high-volume surgeons. 2. Inverse or negative VOA when volume and outcome move in opposite direction i.e. outcome worsens with increasing volume (Note that if outcome is expressed in a negative way i.e. as mortality or complication rate, an inverse VOA means that mortality decreases when volume increases). 3. No association between volume and outcome when there is any change in outcome with increasing volume. 4. Conflicting results on the VOA when some primary studies indicate a positive and others no or a negative relation. These four categories do not reflect other possibilities of the VOA, for example upper limits of the volume effect (reaching asymptotic in quality or decreasing in quality after a certain upper threshold). When the VOA is positive or negative, the statistical significance of the primary studies is summarized between brackets. Statistical significance was set at a level of significance of 5%. • ‘>75% SS’ indicates that three out of four primary studies were statistically significant; • ‘>75% NS’ means that three out of four primary studies showed a statistically not significant trend toward a better or worse outcome in high-volume hospital or high-volume surgeon; • ‘mix SS & NS’ tells the reader that there is a mixture of SS and NS primary studies and that neither of these represent more than 75% of the totality of primary studies. THRESHOLD VOLUMES This is a summary of the thresholds for surgeons or hospitals that were defined in the systematic review or, more often, in the primary studies that were included in the SR. The threshold stands for the annual number of procedures or conditions that is performed or treated in the hospital, or by the surgeon. The threshold can be an exact number. In most cases, however, since several primary studies are summarized, the threshold is presented as a range which means that the defined volume fluctuates between a minimum and a maximum number of procedures. There are four possible thresholds: for a high volume hospital, a low volume hospital, a high volume surgeon and a low volume surgeon. Because of the divergence in definition of a high-volume and low-volume provider, there will often be an overlap between these two thresholds. QUALITY OF EVIDENCE The quality of evidence of the primary studies is assessed for each procedure individually. The objective of this third quality appraisal is to assign an evidence level to the primary studies according to the GRADE system ranging from high (grade A) over moderate (grade B) to low (grade C). 6 In theory, observational studies generally yield only grade C evidence. But Guyatt et al. mention that observational studies with overwhelming evidence can be classified as of grade A quality. In addition, strong evidence from observational studies can be scored as grade B quality. 6
KCE Reports 113 Volume Outcome 11 On the basis of Guyatt’s grades of evidence, four criteria were formulated for the assignment of a Grade B or Grade C level of evidence to primary studies that were analysed in systematic reviews. Grade A level of evidence was considered impossible. 1. Fitness of the SRs to support evidence, as assessed in the second quality appraisal (see Appendix 7): • Grade B: ++ or +++ • Grade C: + 2. Number of primary studies in the SR that study the VOA for this procedure or condition: • Grade B: > 5 primary studies • Grade C: < 5 primary studies 3. Study period of the primary studies: • Grade B: in or after 1988 • Grade C: before 1988 4. Percentage of studies with a positive or negative volume outcome association: • Grade B: at least 75% of primary studies show a statistically significant relation (positive or negative) between volume and outcome • Grade C: at least 75% of primary studies show a statistically not significant relation (positive or negative) between volume and outcome, or there is a mix of statistically significant and not statistically significant primary studies. This last criterion can be criticized as statistical significance depends on size of effects and of sample size. A typical characteristic of volume outcome studies is that sample size depends on the prevalence of the disease or the intervention. CONCLUSION The conclusion on the association between volume (i.e. number of procedures or conditions in hospitals or by surgeons) and the different outcomes will preferably be based on systematic reviews with a Grade B level of evidence. Outcome measures, for which there is insufficient evidence, will not be summarized in the conclusions. In relation to the threshold, an attempt is made to summarize the different thresholds (i.e. high-volume and low-volume) into one single minimal hospital volume threshold, and, if possible, one minimal surgeon volume threshold. Such volume standards seem to make more sense than extensively overlapping thresholds. For some procedures, the thresholds are also based on those issued by organisations such as the US Agency for Healthcare Research and Quality and the US Leapfrog Group. The rationale behind the threshold is explained in the tables of evidence (Appendix 8, 9 and 10). 2.2.3.4 Search protocol in relation to additional primary studies In chapters 5, 6 and 7 of this report, the results of the analysis of the Belgian data will be compared with the results from the scientific literature. For a limited amount of procedures and conditions, the number of studies that was retrieved through the selected systematic reviews was considered insufficient as comparison material for this discussion. For these procedures and conditions, an additional literature search was performed in an attempt to complement the systematic reviews with more recent primary studies. Such an additional search was done for the following procedures: heart valve replacement or repair, hip fracture surgery, oesophageal, pancreatic, colon, breast and lung cancer surgery.
Page 1 and 2: Het volume van chirurgische ingrepe
Page 3 and 4: Het volume van chirurgische ingrepe
Page 5 and 6: KCE reports 113A Volume - Uitkomst
Page 17 and 18: KCE Reports 113 Volume Outcome 1 Sc
Page 19 and 20: KCE Reports 113 Volume Outcome 3 6.
Page 21 and 22: KCE Reports 113 Volume Outcome 5 Ab
Page 23 and 24: KCE Reports 113 Volume Outcome 7 2
Page 25: KCE Reports 113 Volume Outcome 9 5.
Page 29 and 30: KCE Reports 113 Volume Outcome 13 F
Page 31 and 32: KCE Reports 113 Volume Outcome 15 T
Page 33 and 34: KCE Reports 113 Volume Outcome 17 P
Page 49 and 50: KCE Reports 113 Volume Outcome 33 H
Page 73 and 74: KCE Reports 113 Volume Outcome 57 R
Page 77 and 78:
KCE Reports 113 Volume Outcome 61 C
Page 79 and 80:
KCE Reports 113 Volume Outcome 63 A
Page 81 and 82:
KCE Reports 113 Volume Outcome 65 5
Page 83 and 84:
KCE Reports 113 Volume Outcome 67 T
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
KCE Reports 113 Volume Outcome 77 D
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
KCE Reports 113 Volume Outcome 91 F
Page 109 and 110:
KCE Reports 113 Volume Outcome 93 R
Page 111 and 112:
Page 113 and 114:
KCE Reports 113 Volume Outcome 97 V
Page 115 and 116:
Page 117 and 118:
KCE Reports 113 Volume Outcome 101
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
Page 235 and 236:
Page 237 and 238:
Page 239 and 240:
Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
Page 247 and 248:
Page 249 and 250:
Page 251 and 252:
Page 253 and 254:
This page is left intentionally bla
Page 255 and 256:
KCE reports 1. Effectiviteit en kos
Page 257 and 258:
73. Financiering van het zorgprogra
show all

Het volume van chirurgische ingrepen en de impact ervan op ... - KCE

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?