Prevalence (%) and 95% binomial confidence intervals (CIs) of serum protein abnormalities year by year prior to multiple myeloma diagnosis
| Blood draw prior to multiple myeloma diagnosis, y . | M-spike* . | Abnormal kappa-lambda FLC-ratio† . | MGUS‡ . | |||
|---|---|---|---|---|---|---|
| n/N . | % (95% CI) . | n/N . | % (95% CI) . | n/N . | % (95% CI) . | |
| By year§ | ||||||
| 2 | 25/27 | 92.6 (75.7-99.1) | 23/27 | 85.2 (66.3-95.8) | 27/27 | 100.0 (87.2-100.0) |
| 3 | 54/58 | 93.1 (83.3-98.1) | 46/58 | 79.3 (66.7-88.8) | 57/58 | 98.3 (90.8-100.0) |
| 4 | 45/48 | 93.8 (82.8-98.7) | 29/46 | 63.0 (47.6-76.8) | 47/48 | 97.9 (88.9-100.0) |
| 5 | 34/37 | 91.9 (78.1-98.3) | 25/37 | 67.6 (50.2-82.0) | 35/37 | 94.6 (81.8-99.3) |
| 6 | 25/25 | 100.0 (86.3-100.0) | 19/25 | 76.0 (54.9-90.6) | 25/25 | 100.0 (86.3-100.0) |
| 7 | 14/15 | 93.3 (68.1-99.8) | 11/15 | 73.3 (44.9-92.2) | 14/15 | 93.3 (68.1-99.8) |
| 8 or more | 13/17 | 76.5 (50.1-93.2) | 8/17 | 47.1 (23.0-72.2) | 14/17 | 82.4 (56.6-96.2) |
| Trend test | P = .60 | P = .12 | P = .32 | |||
| By year‖ | ||||||
| 2 | 64/70 | 91.4 (82.6-96.8) | 52/70 | 74.3 (62.4-84.0) | 68/70 | 97.1 (90.1-99.7) |
| 3 | 61/67 | 91.0 (81.5-96.6) | 50/67 | 74.6 (62.5-84.5) | 65/67 | 97.0 (89.6-99.6) |
| 4 | 48/53 | 90.6 (79.3-96.9) | 31/52 | 59.6 (45.1-73.0) | 51/53 | 96.2 (87.0-99.5) |
| 5 | 36/41 | 87.8 (73.8-95.9) | 25/41 | 61.0 (44.5-84.1) | 38/41 | 92.7 (80.1-98.5) |
| 6 | 26/28 | 92.9 (76.5-99.1) | 19/28 | 67.9 (47.7-84.1) | 27/28 | 96.4 (81.7-99.9) |
| 7 | 14/16 | 87.5 (61.7-98.5) | 11/16 | 68.8 (41.3-89.0) | 15/16 | 93.8 (69.8-99.8) |
| 8 or more | 13/17 | 76.5 (50.1-93.2) | 8/17 | 47.1 (23.0-72.2) | 14/17 | 82.4 (56.6-96.2) |
| Trend test | P = .43 | P = .13 | P = .34 | |||
| Blood draw prior to multiple myeloma diagnosis, y . | M-spike* . | Abnormal kappa-lambda FLC-ratio† . | MGUS‡ . | |||
|---|---|---|---|---|---|---|
| n/N . | % (95% CI) . | n/N . | % (95% CI) . | n/N . | % (95% CI) . | |
| By year§ | ||||||
| 2 | 25/27 | 92.6 (75.7-99.1) | 23/27 | 85.2 (66.3-95.8) | 27/27 | 100.0 (87.2-100.0) |
| 3 | 54/58 | 93.1 (83.3-98.1) | 46/58 | 79.3 (66.7-88.8) | 57/58 | 98.3 (90.8-100.0) |
| 4 | 45/48 | 93.8 (82.8-98.7) | 29/46 | 63.0 (47.6-76.8) | 47/48 | 97.9 (88.9-100.0) |
| 5 | 34/37 | 91.9 (78.1-98.3) | 25/37 | 67.6 (50.2-82.0) | 35/37 | 94.6 (81.8-99.3) |
| 6 | 25/25 | 100.0 (86.3-100.0) | 19/25 | 76.0 (54.9-90.6) | 25/25 | 100.0 (86.3-100.0) |
| 7 | 14/15 | 93.3 (68.1-99.8) | 11/15 | 73.3 (44.9-92.2) | 14/15 | 93.3 (68.1-99.8) |
| 8 or more | 13/17 | 76.5 (50.1-93.2) | 8/17 | 47.1 (23.0-72.2) | 14/17 | 82.4 (56.6-96.2) |
| Trend test | P = .60 | P = .12 | P = .32 | |||
| By year‖ | ||||||
| 2 | 64/70 | 91.4 (82.6-96.8) | 52/70 | 74.3 (62.4-84.0) | 68/70 | 97.1 (90.1-99.7) |
| 3 | 61/67 | 91.0 (81.5-96.6) | 50/67 | 74.6 (62.5-84.5) | 65/67 | 97.0 (89.6-99.6) |
| 4 | 48/53 | 90.6 (79.3-96.9) | 31/52 | 59.6 (45.1-73.0) | 51/53 | 96.2 (87.0-99.5) |
| 5 | 36/41 | 87.8 (73.8-95.9) | 25/41 | 61.0 (44.5-84.1) | 38/41 | 92.7 (80.1-98.5) |
| 6 | 26/28 | 92.9 (76.5-99.1) | 19/28 | 67.9 (47.7-84.1) | 27/28 | 96.4 (81.7-99.9) |
| 7 | 14/16 | 87.5 (61.7-98.5) | 11/16 | 68.8 (41.3-89.0) | 15/16 | 93.8 (69.8-99.8) |
| 8 or more | 13/17 | 76.5 (50.1-93.2) | 8/17 | 47.1 (23.0-72.2) | 14/17 | 82.4 (56.6-96.2) |
| Trend test | P = .43 | P = .13 | P = .34 | |||
Detectable by electrophoresis, immunofixation, or both.
Normal reference range: 0.26-1.65.
Defined as having evidence of an M-spike (detectable by electrophoresis, immunofixation, or both), an abnormal FLC-ratio (<0.26 or >1.65), or both.
Individuals at risk were based on an actual available serum sample at a given time point (eg, 2 years prior to MM diagnosis) and the results were based on the outcome of assays from that same sample.
Individuals at risk were based on imputed statistical modeling (see further details in “Statistical methods”), where individuals with an available serum samples and with an abnormal finding in an earlier year (eg, 5 years prior to multiple myeloma diagnosis there was evidence of an M-spike) were set to be at risk and to have evidence of an M-spike in the following years (ie, 4, 3, and 2 years prior to MM diagnosis). These models were based on the assumption that once these protein abnormalities are present they do not entirely disappear.